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#Non-Bayesian statistics
art-of-mathematics · 1 year
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Title: "Non-linear regression in a blurry cloud of (un-) certainty"
Date: 2023/06/12 - Size: DIN A4
Collage made with torn pieces of paper, printed background paper (top is rather dark night sky, bottom is mererly clouds in pastel-colors)
I resized and printed the non-linear regression visualisation/illustration and put it on top of the watercolour background paper.
I included a scrap piece of paper with the title of the picture and have torn it with a spiral-shaped jag at the bottom, which I bent around the top part of the non-linear regression illustration.
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frithwontdie · 9 months
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Are Ashkenazi Jews white? Short answer, No!
Ashkenazi Jews may appear white, but are not. Some identify as white and some don't. Even many jewish news articles claim their not white.
But what do the facts say?
Ashkenazi Jews are a genetically and culturally Middle Eastern people, who only began to “integrate” into European society after the rise of Liberalism in the 17th or 18th Century. Their history in Europe has been full of conflict. Being continually massacred, and expelled from every single European country that they have ever inhabited. It was clear that white Europeans considered jews to be categorically separate race from them. (plus the Jews also considered themselves separate from white Europeans as well). Plus the overwhelming majority have distinctly non-European phenotypes that are obviously Middle Eastern in origin.
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Plus, the claim that they're white, is not supported by scientific, genetic evidence.
Despite their long-term residence in different countries and isolation from one another, most Jewish populations were not significantly different from one another at the genetic level.
Admixture estimates suggested low levels of European Y-chromosome gene flow into Ashkenazi and Roman Jewish communities.  Jewish and Middle Eastern non-Jewish populations were not statistically different. The results support the hypothesis that the paternal gene pools of Jewish communities from Europe, North Africa, and the Middle East descended from a common Middle Eastern ancestral population, and suggest that most Jewish communities have remained relatively isolated from neighboring non-Jewish communities during and after the Diaspora.”
The m values based on haplotypes Med and 1L were ~13% ± 10%, suggesting a rather small European contribution to the Ashkenazi paternal gene pool. When all haplotypes were included in the analysis, m increased to 23% ± 7%. This value was similar to the estimated Italian contribution to the Roman Jewish paternal gene pool.
About 80 Sephardim, 80 Ashkenazim and 100 Czechoslovaks were examined for the Yspecific RFLPs revealed by the probes p12f2 and p40a,f on TaqI DNA digests. The aim of the study was to investigate the origin of the Ashkenazi gene pool through the analysis of markers which, having an exclusively holoandric transmission, are useful to estimate paternal gene flow. The comparison of the two groups of Jews with each other and with Czechoslovaks (which have been taken as a representative source of foreign Y-chromosomes for Ashkenazim) shows a great similarity between Sephardim and Ashkenazim who are very different from Czechoslovaks. On the other hand both groups of Jews appear to be closely related to Lebanese. A preliminary evaluation suggests that the contribution of foreign males to the Ashkenazi gene pool has been very low (1 % or less per generation).
Jewish populations show a high level of genetic similarity to each other, clustering together in several types of analysis of population structure. These results support the view that the Jewish populations largely share a common Middle Eastern ancestry and that over their history they have undergone varying degrees of admixture with non-Jewish populations of European descent. We find that the Jewish populations show a high level of genetic similarity to each other, clustering together in several types of analysis of population structure. Further, Bayesian clustering, neighbor-joining trees, and multidimensional scaling place the Jewish populations as intermediate between the non-Jewish Middle Eastern and European populations. These results support the view that the Jewish populations largely share a common Middle Eastern ancestry and that over their history they have undergone varying degrees of admixture with non-Jewish populations of European descent.
A sample of 526 Y chromosomes representing six Middle Eastern populations (Ashkenazi, Sephardic, and Kurdish Jews from Israel; Muslim Kurds; Muslim Arabs from Israel and the Palestinian Authority Area; and Bedouin from the Negev) was analyzed for 13 binary polymorphisms and six microsatellite loci. The investigation of the genetic relationship among three Jewish communities revealed that Kurdish and Sephardic Jews were indistinguishable from one another, whereas both differed slightly, yet significantly, from Ashkenazi Jews. The differences among Ashkenazim may be a result of low-level gene flow from European populations and/or genetic drift during isolation.
Archaeologic and genetic data support that both Jews and Palestinians came from the ancient Canaanites, who extensively mixed with Egyptians, Mesopotamian and Anatolian peoples in ancient times. Thus, Palestinian-Jewish rivalry is based in cultural and religious, but not in genetic, differences.
One study 2010 study stated that Both Ashkenazi Jews and Sephardic jews share only 30% European DNA with the rest being of middle east decent. And by a recent 2020 study on remains from Bronze Age (over 3000 years ago) southern Levantine (Canaanite) populations suggests Ashkenazi Jews derive more than half of their ancestry from Bronze Age Levantine populations with the remaining 41% of their ancestry being European and 50% being Middle Eastern.
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midautumngame · 1 year
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Steve
Pronouns: he/him "I admit, I got a little overenthusiastic there.”
Steve had some non-trivial success in the tech world. He loves kombucha, bayesian statistics and an agile workflow! As the VP of the photo sharing platform, Ideate, he's sponsoring the anime con Sakurafest as it makes its big return to Nambo Quay.
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Tell me a story about a piranha in a bathtub
Sylvie isn't exactly a piranha, but there is something piranha-like about Sylvie.
(Piranhas are famously vicious, of course, but in comparison with the other members of their family, they are extremely tame. For most of their lives, when not breeding, they swim lazily, most of the time, with little else to do but cruise, occasionally opening their tiny jaws in the hopes of catching some flying insect.)
The best analogy for Sylvie, if a very rough one, is one used by E. T. Jaynes. Imagine, he said, that you are trying to estimate a typical value of a probability, in a context where you know some more precise information about the probability ("a non-Bayesian prior") but the prior is not known exactly. The way you estimate the probability, in this case, is very simple:
Compute the distance between the current estimate and the most extreme prior you think could be the true one
Go to the nearest most extreme value of the distribution you are currently considering
Repeat until you converge
As Jaynes pointed out, this algorithm is very well-defined and has nice properties. Among other things, it is invariant under continuous changes of distribution, which makes it a convenient way to do things like "estimate mean and variance" or "estimate the expected value of a function."
But, like all Bayesian algorithms, this one has a flaw. Jaynes called it the "cherry-picking problem." If the prior contains two very similar distributions, it is easy to "find an example" of one such distribution, and hence to conclude that the probability is close to 50-50% between the two. This can be hard to understand, given the way it's done in nature: the probabilities of extreme outcomes are always low, but when you chop up the density function into more and more pieces you can find an extreme value in the majority of cases, simply by choosing a fine enough slice. (At least in Jaynes' version of the problem, which avoided other issues like this by being about finite numbers. He demonstrated that if your density function is merely integrable, this kind of cherry-picking works for probabilities as well; this probably sounds like a technical point, but in fact in nature the distribution of anything finite never converges to a limit, so this is a serious caveat.)
Anyway, in nature we can see something like this effect all the time in the media, or in things like sports statistics. The headlines say, say,
"CONDUCTOR SAYS THERE IS 'ABSOLUTELY' A CHANCE OF ME BEING A GIANT GIRAFFE"
What this really means is that it is possible to be a conductor and believe that it is "absolutely" certain that one will not be a giant giraffe. That there is, if not no possibility at all, then no possibility one can imagine. But that is an extraordinarily strong assertion. Of course there's no giraffe going to come in and gnaw off my head right now, or make a hole in the wall the size of Switzerland, or stab me with a glittering sword that grows hotter the longer I'm hit with it, or anything else that it is pretty safe to say will not happen. But on what basis do I say "never" about those things? Do I have a theoretical account, backed up with a proof, of why I am so confident that none of those things will ever happen? Of course I don't. I think I am very likely not to be those things. But at some level, I can imagine anything happening to me. And this, quite clearly, has to be the case, or else we are left with an absurd difficulty, like that mentioned by Jaynes. You'd have to produce a detailed list of everything that can and can't ever happen to you, or . . . well, you could say that that can't happen, but that would violate the principle. You'd have to write off human existence, really, which is an absurdity we'd all like to avoid.
So, okay. But why is this about Sylvie? Well, it's a post about a fictional character named "Sylvie." If you just look at what Sylvie says, it looks like he is making assertions with total confidence. A "piranha" is something that says that if you give it some input, it will either output a binary bit that says "yes" with total confidence or output a binary bit that says "no" with same. It is a machine that says "arguing with me is useless" if that is the conclusion it reached, and "I don't understand what you're saying" if that is the conclusion it reached.
These are common observations about Sylvie, but they are questionable. Let's start with "arguing with me is useless." This gets asserted with great frequency, but when is the last time you saw it provided with a theoretical account of its truth? Sylvie has a human's own utility function, plus an extra component which is supposed to represent his "agentness." As time goes on, we learn that this "agentness" has its own sub-components, including what you might call "the desire to avoid irritating the humans around you" and "the desire not to 'talk into the void.' "
When Sylvie says something about "the fundamental value that is me" he is not talking about his utility function, as this is only in part what motivates him; in the vast majority of cases he can be made, in some sense, happy by going against this function. But this is not true for the "agentness" functions, which pretty much just involve his own internal state. If he tells you that his "agentness" is such that he is going to ask a question, he means that his "agentness" will eventually make him do the question, even if he is aware that this is irritating and unwise, or that it will result in a statement that is pointless (his utility function will say "yes" or "no" at the end).
It's not a fully distinct decision, though, and this is a subtlety that would be hard to figure out if you only paid attention to the surface level of his words. You would have to get into his head a little to really see what is going on. And this can be misleading. You can "get into Sylvie's head" through the parts of it that are exposed to you and have to assume a lot about the rest. This is tricky. It's one thing to go, as he does, from
"please do not do that"
to
"not doing that is the right thing to do"
But it's extremely hard to convince me that this means
"I have a separate 'intelligence' as well as my utility function, and this intelligence is all that is me, and it is certain about everything that it thinks, and it has no counterparts and cannot be simulated or understood, and it is perfect and has no competing interests"
Because, well, nothing does. And if you get into the same place in your head as Sylvie, you tend to conclude some things that aren't true. At the very least, you can't be sure they're not true. This is what I've tried to say before with "Sylvie is not hyperintelligent." He talks like he is, but fundamentally he is not. The answer is that you are not hyperintelligent. You are a human. You make approximations, and assumptions, and you do not have sufficient data to know that the approximations you make are very good approximations, and you can't be sure that the assumptions you make are always false, and so forth.
It's all very complicated, but that is why he is not certain about everything he says. Not because he is more certain than anyone, but because we are, as he says, finite. He is pretty sure that he knows what his utility function wants, and he is a pure machine that knows how to churn through the problems of utility maximization. But every other statement, every other concept he makes, is an approximation or simplification. Sometimes he thinks that an approximation works, but it doesn't, and then he'll realize this.
His statements about AI are pretty uninteresting. They're not really any better than the statements any of the rest of us make about AI and its future prospects. When he says something like "a piranha could have been helpful to me here" he is sort of . . . right. If he
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blogbyahad · 7 days
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How can I grow from a data analyst to a data scientist?
1. Enhance Your Programming Skills
Learn Advanced Python/R: Gain proficiency in programming languages commonly used in data science, focusing on libraries for data manipulation (Pandas, NumPy) and machine learning (Scikit-learn, TensorFlow, PyTorch).
Practice Coding: Engage in coding challenges on platforms like LeetCode or HackerRank to strengthen your problem-solving skills.
2. Deepen Your Statistical Knowledge
Advanced Statistics: Familiarize yourself with concepts like hypothesis testing, regression analysis, and statistical significance. Understanding Bayesian statistics can also be beneficial.
Mathematics: Brush up on linear algebra and calculus, which are foundational for understanding algorithms in machine learning.
3. Learn Machine Learning
Practical Application: Work on projects where you apply machine learning algorithms to real-world datasets, focusing on both supervised and unsupervised learning.
4. Gain Experience with Big Data Technologies
Familiarize with Tools: Learn about tools and frameworks like Apache Spark, Hadoop, and databases (SQL and NoSQL) that are crucial for handling large datasets.
Cloud Services: Explore cloud platforms (AWS, Google Cloud, Azure) to understand how to deploy models and manage data storage.
5. Build a Portfolio
Real Projects: Work on projects that demonstrate your ability to analyze data, build models, and derive insights. Use platforms like GitHub to showcase your work.
Kaggle Competitions: Participate in Kaggle competitions to gain hands-on experience and learn from the community.
6. Network and Collaborate
Connect with Professionals: Attend meetups, webinars, and conferences to network with data scientists and learn about industry trends.
Seek Mentorship: Find a mentor who can guide you through your transition, offering advice and feedback on your progress.
7. Develop Soft Skills
Communication: Focus on improving your ability to communicate complex data findings to non-technical stakeholders. Consider practicing through presentations or writing reports.
Critical Thinking: Enhance your problem-solving and analytical thinking skills, as they are crucial for identifying and framing data science problems.
8. Stay Updated
Follow Trends: Keep up with the latest advancements in data science by reading blogs, listening to podcasts, and following key figures in the field on social media.
Continuous Learning: Data science is a rapidly evolving field. Engage in lifelong learning to stay relevant and informed about new tools and techniques.
9. Consider Advanced Education
Certificates or Degrees: Depending on your career goals, consider pursuing a master’s degree in data science or specialized certificates to deepen your knowledge and credentials.
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coineagle · 16 days
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US Economic Trends: Deciding Factor in Bitcoin’s Push Toward $50k or $80k?
Key Points
The crypto market is sensitive to US macro data prints due to the absence of significant catalysts.
Bitcoin’s weekly Relative Strength Index closed at its lowest level since January 2023.
The crypto market is currently susceptible to US macro data prints, due to a lack of significant catalysts.
The weekly Relative Strength Index (RSI) reading of Bitcoin (BTC) closed at its lowest level since January 2023.
Bitcoin’s Market Performance
On 9th September, Bitcoin briefly climbed above $55,500 after mild losses heading into the weekend, which resulted in negative returns of 4.26% for the week.
Despite not being as deep as the 11% slide in the preceding week, the slightly underwhelming close marked consecutive weekly losses for Bitcoin since 10th June.
Last week’s dip was attributed to the U.S. non-farm payroll data and negative flows from Bitcoin ETFs.
The latest U.S. jobs report revealed that the economy added 142,000 non-farm payrolls in August, falling short of the expected 160,000.
Upcoming Influences on the Market
This week, market participants are anticipating more U.S. economic data that could influence the Federal Reserve’s 18th September rate decision and impact the overall market direction.
The Bureau of Labor Statistics will release August’s U.S. Consumer Price Index report and the Producer Price Index data.
Analysts at Bernstein have pointed out that the outcome of the upcoming US Presidential debate and the nature of the regulatory environment are not accounted for in the current market.
They forecast that Bitcoin could fall to the $30,000 to $40,000 range if Democrat nominee Kamala Harris is elected as President.
In contrast, a Trump victory in the November elections could propel Bitcoin above $80,000 by the fourth quarter.
Bitcoin’s Future Price Predictions
Chart trader Peter Brandt noted that technical indicators are increasingly leaning in favor of his initial low $30,000 range projection.
He stated,
““Currently, my Bayesian Probability for sub-$40,000 is at 65% with a yet-to-be-achieved top at $80,000 at 20% and an advance during this halving cycle to $130,000 by September 2025 at 15%.””
Markus Thielen, founder of 10x Research, also opined that Bitcoin reached a cycle top in April, drawing attention to reduced Bitcoin network activity after Q1.
Despite the sluggish trading since the halving, some analysts contend that Bitcoin is poised for further gains based on the price action in previous halving years.
Bitcoin is currently trading near $55,400 after posting the lowest weekly close since late February.
The BTC weekly RSI similarly closed at its lowest level since the start of 2023.
Bitcoin order books hint at a potential bullish setup on the horizon, as does the Bitcoin CME futures chart.
Bitcoin futures opened higher than last week, moving back into a descending wedge pattern after briefly breaking below it.
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flipante · 20 days
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humans did not spend centuries developing the concept of randomness and probabilty, formalizing it with kolmogorov axioms, extending it to statistics, discussing the confirmation and survivorship bias, arguing over frequentism vs bayesian inference, delving into biased sampling, etc. for you to base your sociological attitudes in some few experiences / events news.
like yeah, I can point out people who detransition, women who falsely accused of SA, a gay pedophile, we are 7 billion people in the planet, it would be worrisome if you could not
but this means nothing. you see 10 news in a row talking about an immigrant doing crime only last week, okay, was the total number higher than 10? how does it compare to non-immigrants? how does it compare to other times? what's the difference between supported and unsupported immigrants? why are you, the news, not saying anything about this things? why do people believe news is a way of gaining information? when it clearly isn't?
just because the news is not fake, doesn't mean it's statistically significant, karen
why did we put so much effort for nothing
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fMRI Data Analysis Techniques: Exploring Methods and Tools
Functional magnetic resonance imaging has changed the existing view of the human brain. Because it is non-invasive, access to neural activity is acquired through blood flow changes. Thus, fMRI provides a window into the neural underpinnings of cognition and behaviour. However, the real power of fMRI is harnessed from sophisticated image analysis techniques that translate data into meaningful insights.
A. Preprocessing:
Preprocessing in fMRI data analysis is one of the most critical steps that aim at noise and artefact reduction in the data while aligning it in a standard anatomical space. Necessary preprocessing steps include:
Motion Correction: The fMRI data are sensitive to the movement of the patient. Realignment belongs to one of those techniques that modify the motion by aligning each volume of the brain to a reference volume. Algorithms used for this purpose include SPM-Statistical Parametric Mapping-or FSL-FMRIB Software Library.
Slice Timing Correction: Since the slices of functional magnetic resonance imaging are acquired at times slightly shifted from one another, slice timing correction makes adjustments that ensure synchrony across brain volumes. SPM and AFNI are popular packages for doing this.
Spatial Normalisation: It is a process in which data from every single brain is mapped onto a standardised template of the brain. This thus, enables group comparisons. Tools like SPM and FSL have algorithms that realise precise normalisation.
Smoothening: Spatial smoothening improves SNR by averaging signal of the neighboring voxels. This can be done using a Gaussian kernel and generally done using software packages such as SPM and FSL.
B. Statistical Modelling:
After the pre-processing stage, statistical modelling techniques are applied to data to reveal significant brain activity. The important ones are:
General Linear Model (GLM): GLM is the real workhorse of fMRI analysis. It models, among other things, experimental conditions in relation to brain activity. In SPM, FSL, and AFNI, there is a very solid implementation of the general linear model that will allow a researcher to test hypotheses about brain function.
MVPA: Unlike GLM, which considers the activations of single voxels, MVPA considers the pattern of activity in many voxels together. This provides much power in decoding neural representations and is bolstered by software such as PyMVPA and PRoNTo.
Bayesian Modelling: Bayesian methods provide a probabilistic framework for interpreting fMRI within a statistical environment that includes prior information. Bayesian estimation options are integrated into SPM, permitting more subtle statistical inferences.
C. Coherence Analysis:
Connectivity analysis looks at the degree to which activity in one brain region is related to activity in other brain regions and hereby reveals the network structure of the brain. Some of the main approaches are as follows:
Functional Connectivity: It evaluates the temporary correlation between different brain regions. CONN, which comes as part of the SPM suite, and FEAT of FSL can perform functional connectivity analysis.
Effective Connectivity: Whereas functional connectivity only measures the correlation, effective connectivity models the causal interactions between different brain regions. Dynamic causal modelling, as offered in SPM also, is one such leading metric for this analysis.
Graph Theory: Graph theory techniques model the brain as a network with nodes (regions) and edges (connections), thus enabling the investigation of the topological characteristics of the brain. Some critical tools available in graph theoretical analysis include the Brain Connectivity Toolbox and GRETNA.
D. Software for fMRI Data Analysis
A few software packages form the core of the analysis of fMRI data. Each has its strengths and areas of application:
SPM (Statistical Parametric Mapping)- a full set of tools for preprocessing, statistical analysis, and connectivity analysis.
FSL (FMRIB Software Library)- a strong set of tools for preprocessing, GLM-based analysis, and several methods of connectivity.
AFNI (Analysis of Functional NeuroImages)- a package favoured because of its flexibility and fine-grained options in preprocessing.
CONN- Functional connectivity analysis is very strongly linked with SPM.
BrainVoyager- a commercial package that offers a very friendly user interface and impressive visualisation.
Nilearn- a Python library using machine learning for Neuroimaging data, targeting researchers experienced with Python programming.
Conclusion
fMRI data analysis comprises a very diverse field. Preprocessing, statistical modelling, and connectivity analysis blend together to unlock the mysteries of the brain. Methods presented here, along with their associated software, build the foundation of contemporary neuroimaging research and drive improvements in understanding brain function and connectivity.
Many companies, like Kryptonite Solutions, enable healthcare centres to deliver leading-edge patient experiences. Kryptonite Solutions deploys its technology-based products from Virtual Skylights and the MRI Patient Relaxation Line to In-Bore MRI Cinema and Neuro Imaging Products. Their discoveries in MRI technology help provide comfort to patients and enhance diagnostic results, able to offer the highest level of solutions for modern healthcare needs.
Be it improving the MRI In-Bore Experience, integrating an MRI-compatible monitor, availing the fMRI monitor, or keeping updated on the latest in fMRI System and MRI Healthcare Systems, all the tools and techniques of fMRI analysis are indispensable in any modern brain research.
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aanandh · 29 days
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Advanced Statistical Techniques with Clinical SAS: What You Need to Know
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Clinical SAS (Statistical Analysis System) is a powerful tool used extensively in the pharmaceutical and healthcare industries for managing and analyzing clinical trial data. Among its many capabilities, SAS excels in advanced statistical techniques that are essential for complex clinical research. This blog delves into some of these techniques, how they are implemented in SAS, and their applications in clinical trials.
Understanding Advanced Statistical Techniques
Advanced statistical techniques go beyond basic data analysis to address more complex questions and scenarios in clinical research. These techniques often involve sophisticated modeling, predictive analytics, and hypothesis testing to provide deeper insights and support decision-making. Here’s an overview of key advanced statistical methods used in Clinical SAS:
Mixed ModelsMixed models (also known as hierarchical models or multilevel models) are used to analyze data with multiple levels of variation. They are particularly useful in clinical trials where data are collected at different levels (e.g., patients within different treatment groups). SAS’s PROC MIXED provides a framework for fitting mixed models, allowing researchers to account for both fixed and random effects in their analyses. This technique is valuable for analyzing longitudinal data and repeated measures.
Survival AnalysisSurvival analysis focuses on time-to-event data, which is crucial in clinical trials for evaluating the efficacy of treatments over time. SAS offers several procedures for survival analysis, including PROC LIFETEST for Kaplan-Meier estimates and PROC PHREG for Cox proportional hazards models. These tools help assess the effect of treatments on time-to-event outcomes, such as time to disease progression or overall survival.
Bayesian AnalysisBayesian methods incorporate prior information and update probabilities as new data become available. This approach is useful for adaptive designs and decision-making in clinical trials. SAS’s PROC MCMC (Markov Chain Monte Carlo) facilitates Bayesian analysis, allowing researchers to perform complex simulations and derive posterior distributions. Bayesian methods are especially beneficial for incorporating expert knowledge and handling small sample sizes.
Mixed-Effects Models for Meta-AnalysisMeta-analysis involves combining results from multiple studies to provide a more comprehensive understanding of treatment effects. Mixed-effects models are used in meta-analysis to account for variability between studies. SAS’s PROC MIXED and PROC NLMIXED are used for fitting these models, enabling researchers to combine data from different sources and assess overall treatment efficacy.
Generalized Estimating Equations (GEE)Generalized Estimating Equations are used for analyzing correlated data, such as repeated measurements on the same subjects. GEEs handle the correlation between observations and provide robust estimates for parameters. SAS’s PROC GENMOD allows researchers to implement GEEs and analyze data with non-normal distributions, such as binary or count data.
Structural Equation Modeling (SEM)Structural Equation Modeling is a comprehensive technique used to assess complex relationships between variables. SEM allows researchers to model direct and indirect effects and assess the fit of theoretical models to empirical data. SAS’s PROC CALIS supports SEM, providing tools for specifying, estimating, and evaluating structural models.
Multivariate AnalysisMultivariate analysis involves examining multiple variables simultaneously to understand their relationships and effects. Techniques such as principal component analysis (PCA) and factor analysis are used to reduce dimensionality and identify underlying structures in data. SAS offers PROC FACTOR for factor analysis and PROC PRINCOMP for PCA, helping researchers explore and interpret complex datasets.
Cluster AnalysisCluster analysis groups similar observations into clusters based on their characteristics. This technique is useful for identifying patterns and segments within clinical trial data. SAS’s PROC CLUSTER and PROC FASTCLUS provide tools for hierarchical and k-means clustering, enabling researchers to categorize subjects based on various attributes.
Time Series AnalysisTime series analysis is used to analyze data collected over time to identify trends, seasonal effects, and other temporal patterns. SAS’s PROC ARIMA and PROC TIMESERIES support time series modeling, allowing researchers to analyze and forecast outcomes based on historical data.
Decision Trees and Random Forests
Decision trees and random forests are machine learning techniques used for classification and prediction. These methods can handle large datasets and complex interactions between variables. SAS’s PROC HPSPLIT and PROC HPFOREST are used for implementing decision trees and random forests, providing tools for predictive modeling and variable selection.
Implementing Advanced Techniques in Clinical SAS
Clinical SAS provides a range of procedures and options for implementing advanced statistical techniques. Researchers can utilize SAS’s extensive documentation and resources to understand the syntax and options available for each technique. Here are some tips for effectively using these methods:
Familiarize Yourself with SAS Procedures: Each advanced statistical technique in SAS is implemented through specific procedures (e.g., PROC MIXED for mixed models). Review the documentation and examples provided by SAS to understand how to use these procedures effectively.
Leverage SAS Macros: SAS macros can automate repetitive tasks and streamline complex analyses. Creating custom macros for advanced techniques can enhance efficiency and reproducibility.
Validate Your Models: It’s important to validate the models and results obtained from advanced statistical techniques. Use diagnostic tools and validation procedures to ensure the accuracy and robustness of your findings.
Stay Updated: SAS frequently updates its software with new features and enhancements. Stay informed about the latest developments and best practices to make the most of SAS’s advanced capabilities.
Conclusion
Advanced statistical techniques in Clinical SAS play a crucial role in analyzing complex clinical trial data and deriving meaningful insights. From mixed models and survival analysis to Bayesian methods and machine learning, SAS provides a comprehensive suite of tools for addressing diverse research questions. By leveraging these techniques, researchers can enhance their understanding of treatment effects, improve decision-making, and contribute to the advancement of medical science.
Whether you are conducting longitudinal studies, analyzing time-to-event data, or combining results from multiple studies, mastering these advanced techniques in Clinical SAS will empower you to tackle complex research challenges and achieve more accurate and insightful results.
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excelrthane1 · 2 months
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Introduction to Data Science: A Comprehensive Guide for Beginners
Data science is an interdisciplinary field that uses scientific methods, processes, algorithms, and systems to extract knowledge and insights from structured and unstructured data. It combines aspects of statistics, computer science, and domain expertise to analyze and interpret complex data sets. As businesses and organizations increasingly rely on data-driven decision-making, the demand for skilled data scientists continues to grow. This comprehensive guide provides an introduction to data science for beginners, covering its key concepts, tools, and techniques.
What is Data Science?
Data science Course is the practice of extracting meaningful insights from data. It involves collecting, processing, analyzing, and interpreting large volumes of data to identify patterns, trends, and relationships. Data scientists use various tools and techniques to transform raw data into actionable insights, helping organizations make informed decisions and solve complex problems.
Key Concepts in Data Science
1. Data Collection
The first step in the data science process is data collection. This involves gathering data from various sources such as databases, APIs, web scraping, sensors, and more. The data can be structured (e.g., spreadsheets, databases) or unstructured (e.g., text, images, videos).
2. Data Cleaning
Raw data is often messy and incomplete, requiring cleaning and preprocessing before analysis. Data cleaning involves handling missing values, removing duplicates, correcting errors, and transforming data into a consistent format. This step is crucial as the quality of the data directly impacts the accuracy of the analysis.
3. Data Exploration and Visualization
Data exploration involves analyzing the data to understand its characteristics, distributions, and relationships. Visualization tools such as matplotlib, seaborn, and Tableau are used to create charts, graphs, and plots that help in identifying patterns and trends. Data visualization is an essential skill for data scientists as it enables them to communicate their findings effectively.
4. Statistical Analysis
Statistical analysis is at the core of data science. It involves applying mathematical techniques to summarize data, make inferences, and test hypotheses. Common statistical methods used in data science include regression analysis, hypothesis testing, and Bayesian analysis. These techniques help in understanding the underlying patterns and relationships within the data.
5. Machine Learning
Machine learning is a subset of artificial intelligence (AI) that enables computers to learn from data and make predictions or decisions without being explicitly programmed. It involves training algorithms on historical data to identify patterns and make accurate predictions on new data. Common machine learning algorithms include linear regression, decision trees, support vector machines, and neural networks.
6. Data Interpretation and Communication
The final step in the data science process is interpreting the results and communicating the findings to stakeholders. Data scientists need to translate complex analyses into actionable insights that can be easily understood by non-technical audiences. Effective communication involves creating reports, dashboards, and presentations that highlight the key insights and recommendations.
Tools and Technologies in Data Science
Data scientists use a variety of tools and technologies to perform their tasks. Some of the most popular ones include:
- Python: A versatile programming language widely used in data science for its simplicity and extensive libraries such as pandas, NumPy, and scikit-learn.
- R: A programming language and software environment specifically designed for statistical analysis and visualization.
- SQL: A language used for managing and querying relational databases.
- Hadoop and Spark: Frameworks for processing and analyzing large-scale data.
- Tableau and Power BI: Visualization tools that enable data scientists to create interactive and informative dashboards.
Applications of Data Science
Data science has a wide range of applications across various industries, including:
- Healthcare: Predicting disease outbreaks, personalized medicine, and improving patient care.
- Finance: Fraud detection, risk management, and algorithmic trading.
- Marketing: Customer segmentation, targeted advertising, and sentiment analysis.
- Retail: Inventory management, demand forecasting, and recommendation systems.
- Transportation: Optimizing routes, predicting maintenance needs, and improving safety.
Getting Started with Data Science
For beginners interested in pursuing a career in data science, here are some steps to get started:
1. Learn the Basics: Familiarize yourself with fundamental concepts in statistics, programming, and data analysis.
2. Choose a Programming Language: Start with Python or R, as they are widely used in the field.
3. Practice with Real Data: Work on projects and datasets to apply your knowledge and gain hands-on experience.
4. Take Online Courses: Enroll in online courses or attend bootcamps to learn from experts and build your skills.
5. Join a Community: Participate in data science forums, meetups, and competitions to network with other professionals and stay updated with industry trends.
Conclusion
Data science Course in Mumbai is a dynamic and rapidly evolving field with immense potential for innovation and impact. By mastering the key concepts, tools, and techniques, beginners can embark on a rewarding career that leverages the power of data to drive decision-making and solve real-world problems. With the right skills and mindset, you can unlock the limitless possibilities that data science has to offer.
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evoldir · 3 months
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Fwd: Postdoc: UAberdeen.EvolutionaryEcol
Begin forwarded message: > From: [email protected] > Subject: Postdoc: UAberdeen.EvolutionaryEcol > Date: 26 June 2024 at 05:11:47 BST > To: [email protected] > > > > Postdoctoral Research Fellow in Evolutionary Ecology > > School of Biological Sciences, University of Aberdeen, UK > > Fully funded for 3.5 years, closing date for applications July 15th 2024 > > The primary project objectives are to quantify selection and genetic > variation underlying expression of diverse forms of seasonal migration > versus residence, and to predict the implications for eco-evolutionary > dynamics in seasonally mobile systems. This will be achieved using > advanced statistical analyses of multi-year field data from a system of > partially migratory birds in Scotland. > > The successful applicant will lead the development and application of > statistical models to quantify spatio-temporal variation in selection > acting on non-breeding season location, and hence on the form of seasonal > migration versus residence.  The post will suit an applicant with wide > interests in utilising field data to address conceptual questions in > ecology and/or evolutionary biology. > > The ideal candidate will have demonstrated interests in understanding > population, behavioural and/or evolutionary ecology in wild populations, > and in working at the interface between statistical and empirical > advances. They will have strong quantitative skills, including advanced > statistical analyses (which could include generalized linear mixed models, > capture-mark-recapture analyses and/or Bayesian analyses, although further > training will be provided). They will ideally have some experience of > working on relevant topics, for example involving demography, evolutionary > ecology, seasonal migration or other forms of movement or life-history > variation in wild populations. They will have demonstrated abilities to > work effectively as part of a collaborative research team, including > excellent written and verbal communication skills. They will also be > self-motivated and able to work independently on a day-to-day basis. > > The post is part of a UK NERC Pushing the Frontiers research project, > aiming to understand eco-evolutionary dynamics involving partial seasonal > migration. It provides an exciting opportunity for a postdoctoral > researcher to contribute to major new attempts to predict such > eco-evolutionary dynamics in nature. > > The researcher will be based primarily in the School of Biological > Sciences, University of Aberdeen, UK. There will be close working > collaborations with researchers at Norwegian University of Science > and Technology (NTNU, Norway) and UK Centre for Ecology & Hydrology > (Edinburgh, UK, Professor Francis Daunt), with opportunities for extended > visits to these groups. > > Apply at www.abdn.ac.uk/jobs > > Enquiries to Professor Jane Reid ([email protected]) are welcome. > > The University of Aberdeen is a charity registered in Scotland, No SC013683. > Tha Oilthigh Obar Dheathain na charthannas cl�raichte ann an Alba, �ir. SC013683. > > "Reid, Dr Jane M."
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passiveincomemoney · 5 months
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How To Conduct Market Research And Validate Your Business Idea
Market research is an essential component of strategic business planning. It provides valuable insights into your target market, competition, and overall industry landscape. Here's a step-by-step guide to conducting effective market research:
Step 1: Define Your Research Objectives
Begin by clearly defining what you want to achieve with your market research. This could involve understanding consumer behaviour, determining the viability of a new product, or assessing the competitive landscape.
Step 2: Develop Your Research Plan
Decide on the methodology you will use to gather data. This could include surveys, interviews, focus groups, or observational studies. Consider the sample size and the demographic of participants that will provide the most relevant data.
Step 3: Collect the Data
Execute your research plan and start collecting data. Ensure that the data collection methods are ethical and that participants have given informed consent.
Collecting data for market research can be done in various ways, each with its advantages. Here are three effective methods to gather the data you need for insightful market research.
Surveys and Questionnaires Surveys and questionnaires are one of the most common methods of data collection for market research. They can be distributed in various formats, such as online surveys, telephone interviews, or paper questionnaires. This method allows businesses to reach a large audience quickly and at a relatively low cost. Surveys are particularly useful for collecting quantitative data that can be easily analysed statistically.
Interviews and Focus Groups Interviews and focus groups offer a more qualitative approach to data collection. While interviews involve one-on-one sessions with individuals, focus groups gather a small group of people to discuss and provide feedback on a particular topic.
Observation-Based Research Observation-based research involves watching how consumers interact with products or services in a natural setting. This can be done in-person, such as in a retail environment, or through digital means, like tracking user interactions on a website. Observation helps researchers gather data on actual behaviour rather than self-reported behaviour, which can sometimes be biased or inaccurate.
Step 4: Analyse the Data
Once you have collected the data, analyse it to identify patterns, trends, and insights. Use statistical tools and software to help you interpret the data accurately.
Here's a look at some top free resources available today.
JASP: A user-friendly, open-source software that offers both classical and Bayesian analysis methods. It's designed with an intuitive interface, making it accessible for users of all levels.
Statisty: This online app provides a platform for statistical analysis directly in your browser. It's a convenient option for those who prefer not to install software and covers a range of tests from t-tests to regression.
R: A programming language and free software environment for statistical computing and graphics, R is highly extensible and provides a wide variety of statistical and graphical techniques.
Python: With libraries such as NumPy, Pandas, and SciPy, Python is a powerful tool for statistical analysis. It's particularly well-suited for those who are also interested in programming and data science.
PSPP: An alternative to SPSS, PSPP is designed for both interactive and non-interactive batch uses. It can perform descriptive statistics, T-tests, ANOVA, and more.
Step 5: Report Your Findings
Prepare a detailed report that summarizes your research methods, data analysis, and findings. Include visual aids like charts and graphs to make the data more accessible.
Step 6: Make Informed Decisions
Use the insights gained from your market research to make informed business decisions. This could involve product development, marketing strategies, or entering new markets.
Step 7: Take Action and Monitor Results
Implement the decisions based on your research and monitor the results. This will help you understand the effectiveness of your actions and guide future research.
Keep in mind that market research isn't a one-time thing. It's a continuous journey. As the market changes and grows, your knowledge of it should too. Making a habit of conducting regular market research is key. It keeps you informed about trends and helps you stay competitive.
By sticking to these steps, you can make sure your market research is comprehensive, precise, and ready to be put into action. This lays a strong groundwork for your business decisions. Enjoy your research!
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estheruary · 9 months
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Your bubble, a guide.
1 - What claims do you accept without evidence?
If someone makes a statement that disagrees with your worldview do you demand sources despite never having required sources for your own position?
2 - What claims do you dismiss despite evidence?
Is your immediate reaction to someone making a statement that disagrees with your worldview with evidence to go online and find articles that affirm your world view without seriously considering that the opposing view might be stronger?
3 - What claims do you interpret failing to realize the purported benefit when implemented as not applying it hard enough?
"Of course it failed, in order for it to work we have to reorient society entirely around its success."
4 - What non-falsifiable claims do you accept?
Does your worldview include positions that are "self-evident", "part of the natural order", "just the way the world works", or "how nature intended?"
This also included claims ceded to an unquestionable authority such as God.
5 - Do you accept any claims that appear to come from a legitimate authority but can be framed to mean almost anything?
These ones a sneaky, they give the impression of having an evidence-based opinion but the conclusion you want is taken without consideration without considering that the data might equally support opposing positions. Lies, damned lies, and statistics.
6 - What claims do you accept about the world that come from fiction?
Are fictional scenarios that conform to your existing worldview accepted as reasonable but ones that run contrary are dismissed as unrealistic or "that would never really happen."
Do you use others' fictional worlds as your basis for viewing the real world?
Now, there's a wrench. I think this kind of personal introspection is good and healthy but the set of Bayesian priors we've accumulated through our experiences function as a very effective bullshit detector and guard against propaganda and manipulation. In a cruel fate I have found trying to maintain this kind of intellectual openness in every interaction makes it harder to navigate difficult questions as you no longer have a mental framework to do any kind of evaluation. But knowing what things you take as given guide on where to look when you find yourself stuck in an apparent contradiction.
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dipbluray · 11 months
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1001* flying fishes at the jellyfish border
Or whatever I’d talk about when I’d talk about RnR in juvenile framework
Statistics’ satisfyingly significant role in frequentist state
It’s just slightly break of the millennium, and prior to most regular bargaining identities, statistics’ research role in the past century coded by data surveyed at rest application, from ubiquity of acrimonious dispense to mutiny of plots of data clouds have either been wear or tear. The identifier component aimed at rejection-based statistical hypotheses or by itself a frequentist framework approach seemingly suggests emphasized statistical model to start with, using either the frequentist or Bayesian framework there are a few steps to aim for the recognized model state. Should you have inquiries on retaining scale of interpretation and understanding the model outputs, the simple presentation of assessment by goodness of data fit to delivery results experimental and survey means from happenstance, aims to stave gap reading at the fore of this millennial article*.
In addition to the probability decision of car ownership, and connectivity to rationality where availability is repeatedly attempted, as much as logically present is consideration of frequency distribution that’s also certain to the degree of any major coin toss. But instead of the probability parts of its constituent value, that could also consider coin toss results as chance, probability distribution is more certainly not the frequency distribution the coin tosses are geared towards but the probability density function it rebuts. Fisher’s framework for a novel account of probability proposes frequency-based results in such historical output order.
How many ways can an artwork compliment, if it is unidentified, in checks, in frames, in backhanded canvas comment. In how many ways can the Titanic identify itself, in folklore, in shipyards, in pagers, in greeting tickets. How can crash tests be conducted on Twitter in stationary wing, on express lanes, on terrain, on Skynet, on patronizing trips. And in how many ways does crime count as criminal offence, in bear disappointment, in gloves and glances, in benefits and charity, or in an acquaintance with buffets. In other words, how many ways can blockchain technology enthusiasts strike up better innovation tips for generations to plead hatecrime in their venues.
As with most statistical computation with stacks of resources afloat, how has innovation played beneficial role in stepping afoot even the toughest data problems presented so far. And as if survey data isn’t enough for crime computing as before, information is crucial in context and code to store frame ever so evidently. But so is counting sheer probabilities as frequency of favorability or law of large numbers over obsession with uncertainty. Bernoulli’s favored obsession with applying probability theory to model ‘subjective probability’ labelled probability of odds against rule of certainty suggests ‘forever probability’ as an index between 0 and 1. And so the probabilities of lottery striking are as absolute as a strawberry bar pick up, it has to be integrated with borderline progression or inferred by inverse non-probability means as Boolean attempt as the cerulean contraband item but with identical apologies and more privacy perhaps.
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Our data, as we show in the Appendix, exhibit the usual "Bayesian bias" problems that are well known in the literature. As an example, in a typical trial of the size in the Appendix, we find that the Bayes estimators have a "median of 0" bias, while the non-Bayes estimators have none. The "Bayesian bias" results are an example of a general "bias" result that is known in the literature to hold for Bayes.
We find that our Bayes-consistent estimators are outperformed by the non-Bayes-consistent estimators at small but not large sample sizes, and in larger samples they are outperformed by the non-Bayes-estimators, who are then outperformed by the Bayes-estimators who are outperformed by the non-Bayes-estimators.
This general pattern holds for the bootstrap, randomization, cross-validation, and many other data generating processes. The Bayes-consistent estimators do well when data are "close" to data generation parameters and so the Bayesian estimates become "good." As the sample gets larger, "good" Bayesian estimates can be outperformed by "good" non-Bayesian estimates, which in turn can be outperformed by the non-Bayes-estimators. This shows the Bayesian bias phenomenon in a general setting: it is a phenomenon that arises for any sampling distribution for the data in the analysis, so long as there is some unknown data generating parameter that can be estimated via Bayes.
The only other situation where we observe bias in the Bayesian estimates are situations where the data-generating parameters are not identified with high prior probability (see the Appendix for examples and the literature). If prior information leads to "shrinkage" then in small samples the Bayesian estimators converge to the true parameters, while in larger samples they converge to something that is consistent in the large but no longer converges to the true values.
(Alfréd Rényi, from a 1994 paper called "Some remarks on the statistical theory of non-Bayesian estimation," available here.)
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