Practical Data Analysis with JMP®

Checking Data for Suitability of Normal Model

We've already noted that there are times when we'll want to ask how well a normal distribution can serve as a model of a real-world population or process. Because there are often advantages to using a normal model, the practical question often boils down to asking if our actual data deviate too grossly from a normal distribution. If not, a normal model can be quite useful.

In this chapter we'll introduce a basic approach to this question, based on the comparison of observed and theoretical quantiles (that is, the types of comparisons we've just made in the prior section). In Chapter 9 we'll return to this topic and refine the approach.

Normal Quantile Plots

In the previous section, we computed three ...