21. Consider the following sample data with mean and standard deviation o f 20.5 and 5.4, respectively.

Class Frequency Less than 10 25 10 up to 20 95 20 up to 30 65 30 o r more 15 n = 200

a. Using the goodness-of-fit test for normality, specify the competing hypotheses in order to determine whether or not the data are normally distributed.

b. Calculate the value o f the test statistic.

c. At the 5% significance level, what is the critical value?

What is the decision rule?

d. What is the conclusion?