The failure of scientists, and particularly students in the sciences, to properly understand the most commonly used statistical concepts in their field has been extensively documented (see e.g. Sotos et al., 2007). Many of the specific misunderstandings are well known … Read more

## Multiple hypothetical comparisons

You don’t actually have to *do* multiple comparisons to have a multiple comparisons problem — comparisons that you might hypothetically have done maybe if the data had been different perhaps will do it. I’ll show you.

Suppose that you’re conducting … Read more

## Misconceptions and useful counterexamples in statistics

This page contains an assortment of useful or informative examples/counterexamples in probability and statistics. I plan to continue updating this page as I come across new examples.

### A Bayes factor which contradicts the posterior

The following is an example of … Read more

## Linear models for quantiles

Most statistical models used in experimental psychology are designed to estimate the mean of a response variable given some set of predictors. This is all well and good when errors are largely symmetric and our predictors are expected to primarily … Read more

## A note on the CLT

Introductory statistics courses (particularly when they’re taught outside of the statistics department) often gloss over the details of the central limit theorem, describing it only as something that let’s you do t-tests without worrying about normality. I recently came across … Read more

## Doing meta-analysis II

I recently collaborated on a meta-analysis investigating the effects of blast-related (i.e. *BOOM*) mild traumatic brain injury (mTBI) on cognitive performance (Karr, et al. 2014). Each of the eight included studies used control and mTBI groups, and reported means and … Read more

## Doing meta-analysis I

Meta-analysis is, broadly, a set of statistical models for combining the results of several research studies in order to summarize the literature, or estimate an effect more precisely than can be done by a single study alone. The actual process … Read more