This is a video about different kinds of influences on ability tests.

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!

A video tutorial about frequency distributions: