# All Questions

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### What is the best introductory Bayesian statistics textbook?

Which is the best introductory textbook for Bayesian statistics? One book per answer, please.
2k views

### Statistical classification of text

I'm a programmer without statistical background, and I'm currently looking at different classification methods for a large number of different documents that I want to classify into pre-defined ...
• 431
327k views

### Why square the difference instead of taking the absolute value in standard deviation?

In the definition of standard deviation, why do we have to square the difference from the mean to get the mean (E) and take the square root back at the end? Can't we just simply take the absolute ...
• 5,885
2k views

### What statistical blogs would you recommend?

What statistical research blogs would you recommend, and why?
489 views

### What are some good frameworks for method selection?

I have been looking into theoretical frameworks for method selection (note: not model selection) and have found very little systematic, mathematically-motivated work. By 'method selection', I mean a ...
• 3,377
12k views

### Power of Holm's multiple comparison testing compared to others [closed]

Following one-way ANOVA, there are many possible follow-up multiple comparison tests. Holm's test (or better, the Holm-Sidak) test has lots of power, but because it works in a stepwise manner, it ...
• 20.9k
11k views

### What is your favorite data visualization blog?

What is the best blog on data visualization? I'm making this question a community wiki since it is highly subjective. Please limit each answer to one link. Please note the following criteria for ...
10k views

### What's the purpose of window function in spectral analysis?

I'd like to see the answer with qualitative view on the problem, not just definition. Examples and analogous from other areas of applied math also would be good. I understand, my question is silly, ...
• 173
70k views

### What are good basic statistics to use for ordinal data?

I have some ordinal data gained from survey questions. In my case they are Likert style responses (Strongly Disagree-Disagree-Neutral-Agree-Strongly Agree). In my data they are coded as 1-5. I don'...
• 1,599
752 views

### How Large a Difference Can Be Expected Between Standard GARCH and Asymmetric GARCH Volatility Forecasts?

I have been using various GARCH-based models to forecast volatility for various North American equities using historical daily data as inputs. Asymmetric GARCH models are often cited as a ...
• 171
497 views

### Robust nonparametric estimation of hazard/survival functions based on low count data

We're trying to use a Gaussian process to model h(t) -- the hazard function -- for a very small initial population, and then fit that using the available data. While this gives us nice plots for ...
• 4,594
2k views

### Where can I find useful R tutorials with various implementations? [duplicate]

I'm using R and the manuals on the R site are really informative. However, I'd like to see some more examples and implementations with R which can help me develop my knowledge faster. Any suggestions?
11k views

### What R packages do you find most useful in your daily work?

Duplicate thread: I just installed the latest version of R. What packages should I obtain? What are the R packages you couldn't imagine your daily work with data? Please list both general and ...
295 views

### A case of survivorship bias?

With the recent FIFA world cup, I decided to have some fun and determine which months produced world cup football players. Turned out, most footballers in the 2010 world cup were born in the first ...
• 183
3k views

### Can someone please explain the back-propagation algorithm? [duplicate]

What is the back-propagation algorithm and how does it work?
• 978
1k views

### Why do US and UK Schools Teach Different methods of Calculating the Standard Deviation?

As I understand UK Schools teach that the Standard Deviation is found using: whereas US Schools teach: (at a basic level anyway). This has caused a number of my students problems in the past as ...
• 576
207k views

### PCA on correlation or covariance?

What are the main differences between performing principal component analysis (PCA) on the correlation matrix and on the covariance matrix? Do they give the same results?
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245 views

### Measuring the effectiveness of a pattern recognition software

Are there any objective methods of assessment or standardized tests available to measure the effectiveness of a software that does pattern recognition?
• 978
27k views

### What is meant by a "random variable"?

What do they mean when they say "random variable"?
• 2,298
1k views

### Clustering of large, heavy-tailed dataset

I have a dataset of 130k internet users characterized by 4 variables describing users' number of sessions, locations visited, avg data download and session time aggregated from four months of activity....
796 views

### Explain data visualization

How would you explain data visualization and why it is important to a layman?
• 978
1k views

### Pseudo-random number generation algorithms

What algorithms are used in modern and good-quality random number generators?
• 1,164
246 views

### Sample problems on logit modeling and Bayesian methods

I'm looking for worked out solutions using Bayesian and/or logit analysis similar to a workbook or an annal. The worked out problems could be of any field; however, I'm interested in urban planning /...
• 1,449
399k views

### Examples for teaching: Correlation does not mean causation

There is an old saying: "Correlation does not mean causation". When I teach, I tend to use the following standard examples to illustrate this point: number of storks and birth rate in Denmark; number ...
6k views

### Modelling a Poisson distribution with overdispersion

I have a data set that I'd expect to follow a Poisson distribution, but it is overdispersed by about 3-fold. At the present, I'm modelling this overdispersion using something like the following code ...
• 775
3k views

### R packages for seasonality analysis [closed]

What R packages should I install for seasonality analysis?
• 1,164
555k views

### What is the meaning of p values and t values in statistical tests?

After taking a statistics course and then trying to help fellow students, I noticed one subject that inspires much head-desk banging is interpreting the results of statistical hypothesis tests. It ...
• 4,414
2k views

### Testing random variate generation algorithms

Which methods are used for testing random variate generation algorithms?
• 1,164
26k views

### What is a standard deviation?

What is a standard deviation, how is it calculated and what is its use in statistics?
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4k views

### Tools for modeling financial time series

What modern tools (Windows-based) do you suggest for modeling financial time series?
112k views

### Finding the PDF given the CDF

How can I find the PDF (probability density function) of a distribution given the CDF (cumulative distribution function)?
• 1,164
283k views

### Bayesian and frequentist reasoning in plain English

How would you describe in plain English the characteristics that distinguish Bayesian from Frequentist reasoning?
• 4,479
307 views

### Forecasting demographic census

What are some of the ways to forecast demographic census with some validation and calibration techniques? Some of the concerns: Census blocks vary in sizes as rural areas are a lot larger than ...
• 1,449
2k views

### How can I adapt ANOVA for binary data?

I have four competing models which I use to predict a binary outcome variable (say, employment status after graduating, 1 = employed, 0 = not-employed) for n subjects. A natural metric of model ...
363 views

### Multivariate Interpolation Approaches

Is there a good, modern treatment covering the various methods of multivariate interpolation, including which methodologies are typically best for particular types of problems? I'm interested in a ...
125k views

### Under what conditions should Likert scales be used as ordinal or interval data?

Many studies in the social sciences use Likert scales. When is it appropriate to use Likert data as ordinal and when is it appropriate to use it as interval data?
• 1,141
43k views

### Locating freely available data samples

I've been working on a new method for analyzing and parsing datasets to identify and isolate subgroups of a population without foreknowledge of any subgroup's characteristics. While the method works ...
178k views

### The Two Cultures: statistics vs. machine learning?

Last year, I read a blog post from Brendan O'Connor entitled "Statistics vs. Machine Learning, fight!" that discussed some of the differences between the two fields. Andrew Gelman responded favorably ...
47k views

### Assessing the significance of differences in distributions

I have two groups of data. Each with a different distribution of multiple variables. I'm trying to determine if these two groups' distributions are different in a statistically significant way. I ...
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7k views

### What are some valuable Statistical Analysis open source projects?

What are some valuable Statistical Analysis open source projects available right now? Edit: as pointed out by Sharpie, valuable could mean helping you get things done faster or more cheaply.
34k views

### What is normality?

In many different statistical methods there is an "assumption of normality". What is "normality" and how do I know if there is normality?
• 1,141
6k views

### Eliciting priors from experts

How should I elicit prior distributions from experts when fitting a Bayesian model?
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3k views

### Algorithms and methods for attribute/feature selection?

I have data with continuous class and I'm searching for good methods to reduce number of attributes. Now I'm using correlation based filters, random forests and Gram–Schmidt algorithm. What I want ...
• 503
4k views

### Algorithms to eliminate or display outliers in a dataset

I am trying to visualize a large multi-dimensional dataset. Each dimension has a different range. Values in one column may range between 0-100 while values in another could range from a few hundred ...
11k views

### Correcting for outliers in a running average

We have a daemon that reads in data from some sensors, and among the things it calculates (besides simply just reporting the state) is the average time it takes for the sensors to change from one ...