In Exercise 10.11, we used the unequal variances procedure to compare population means. The sample standard deviations involved in the comparison were s₁ = 68 and s₂ = 22. Each sample size was 10.
a. Assuming normality, test to see if the corresponding population standard deviations differ by setting equal to .05.
b. Was it reasonable to use the unequal variances procedure to compare population means? Explain.

Data from Exercise 10.11

A large discount chain compares the performance of its credit managers in Ohio and Illinois by comparing the mean dollar amounts owed by customers with delinquent charge accounts in these two states. Here a small mean dollar amount owed is desirable because it indicates that bad credit risks are not being extended large amounts of credit. Two independent, random samples of delinquent accounts are selected from the populations of delinquent accounts in Ohio and Illinois, respectively. The first sample, which consists of 10 randomly selected delinquent accounts in Ohio, gives a mean dollar amount of $524 with a standard deviation of $68. The second sample, which consists of 20 randomly selected delinquent accounts in Illinois, gives a mean dollar amount of $473 with a standard deviation of $22.