A First Course in Statistics, 12th Edition

4.6 Descriptive Methods for Assessing Normality

In the chapters that follow, we learn how to make inferencesInferences can be made about the population on the basis of information contained in the sample. Several of these techniques are based on the assumption that the population is approximately normally distributed. Consequently, it will be important to determine whether the sample data come from a normal population before we can apply these techniques properly.

A number of descriptive methods can be used to check for normality. In this section, we consider the four methods summarized in the following box:

Determining whether the Data Are from an Approximately Normal Distribution

1. Construct either a histogram or stem-and-leaf display for ...