In this tutorial I discuss and present visual representations of covariance. Although covariance is not directly informative, it is a fundamental ingredient in almost all of the most frequently used statistical procedures.

In this tutorial I discuss and present visual representations of covariance. Although covariance is not directly informative, it is a fundamental ingredient in almost all of the most frequently used statistical procedures.

In this video tutorial, I explain why we have standard scores, why there are so many different kinds of standard scores, and how to convert between any two types of standard scores.

Here is my Excel spreadsheet that converts any type of standard score to any other type.

In this video tutorial, I show why the typical description of kurtosis is not quite right and, in some cases, quite wrong.

A video tutorial about why many variables have a normal distribution:

A video tutorial about Expected Value and its relationship with variance:

- Some Rules of Expected Value Computations
- Measuring Variability Using Expected Values
- The Relationship between the Normal Distribution and the Chi Square Distribution
- Raw Moments
- Central Moments
- The 2nd Central Moment (i.e., Variance) in Terms of Raw Moments

A video tutorial about a different of thinking about the meaning of the mean:

In this video, we take a simple question and we make it complicated so that we can make some complicated questions simple.

A video tutorial about probability density functions. They are like histograms on steroids!