Random Variables

Abstract

This chapter extends the ideas of mean, standard deviation, and normal approximation to distributions more general than the binomial. This involves sums and averages of randomly produced numbers. Random variables, introduced in Section 3.1, provide a good notation for this purpose. The concept of the expectation or mean of a random variable is the subject of Section 3.2. Then standard deviation and the normal approximation appear in Section 3.3. In these first three sections, attention is restricted to random variables with a finite number of possible values. The ideas are extended to random variables with an infinite sequence of possible values in Section 3.4, then to random variables with a continuous distribution in the following chapters.