It is very much designed as a course in applied statistics, covering common topics such as types of variables and data, probability theory, hypothesis testing, measures of central tendency and ...

With a correlation that low, there will be some mean regression at work. Think of it this way. Seven door-to-door salesmen go out and sell as many vacuum cleaners as they can on a Sunday.

In my opinion, reversion to the mean is one of the most powerful, but least understood, concepts in statistics. Regression to the mean explains that in many cases data will tend to even out—i.e ...