1. Discuss how a normal probability plot is constructed.
2. If a normal probability plot has the appearance of a straight line, what should we conclude?
METHODS AND APPLICATIONS
3. Consider the sample of 12 incomes given in Example 3.2 (page 105).
a. Sort the income data from smallest to largest, and compute i/(n + 1) for each observation.
b. Compute the standardized normal quantile value Oi for each observation.
c. Graph the normal probability plot for the salary data and interpret this plot. Does the plot indicate that the data are skewed? Explain. DS
Incomes
4. Consider the 20 DVD satisfaction ratings given on page 123. Construct a normal probability plot for these data and interpret the plot.
5. A normal probability plot can be constructed using MINITAB. Use the selections Stat : Basic Statistics : Normality test, and select the data to be analyzed. Although the MINITAB plot is slightly different from the plot outlined in this section, its interpretation is the same. Use MINITAB to construct a normal probability plot of the gas mileage data in Table 3.1 (page 103). Interpret the plot.
Text Book: Business Statics in Practice By BOWERMAN.