STANDARDIZED RANDOM VARIABLE

Sampling histograms that are symmetric and without outliers can be converted to standardized random variables :

which has (1) mean of r.v.Z _k at the origin: Zbar = 0; and (2) variance of r.v. Z _k of any unity: = 1.

This standardized form of the sample r.v. conveniently presents results in terms of the number of standard deviations above or below the mean. This number is often called the "Z-score" and appears as:

A typical pictorial view of this type of distribution is shown in Figure 16.7.

Figure 16.7: The normal distribution.