The second of my two statistics videos to publish this week is about data variability using Data Range and Sample Variance. Range is really easy to figure out and calculate - it's simply the largest value minus the smallest values in a data set. Sample Variance is a little bit harder to understand, but is also really easy to calculate in Excel.
As I am creating these videos, I am also preparing corresponding sets of lecture notes and tutorial exercises. It's not since the days of my PhD research in the 1980s that I used statistics a lot - so I am basically re-learning it all again. There are far more sources of learning today than in the 1980s. In addition to the course book ("Statistics" by James McClave and Terry Sincich), there are a lot of sample files also provided. The Khan Academy provides a lot of Statistics tutorials, and of course there's also plenty of learning material available on the likes of iTunes.
I find making the videos a really good way to learn - I am making immediate use and showing others what I have learned. This is one of the most effective ways to learn according to the Institute for Applied Behavioral Science.