Random Variables

Random variables are one of the central ideas in probability theory, and hence in statistics and econometrics.

Unfortunately, they are also an idea that many students never quite get straight!

We begin by developing some intuition for what a random variable actually is. We then distinguish between discrete and continuous random variables, before introducing the main mathematical tools used to describe their distributions: probability mass functions, probability density functions, and cumulative distribution functions.

These ideas will turn up repeatedly later, so it is well worth getting comfortable with them now.