Marketing managers for a toy store located in two separate cities is interested in estimating the difference in the mean daily sales for the two cities. They want to calculate a 90 percent confidence interval and will select a sample of 10 days in each store for the study. If the marketing managers assume that the population standard deviations are known, the critical value for the confidence interval is z = 1.645.

Question

Quizplus · Accepted Answer

For a 90% confidence interval with known population standard deviations, the critical value from the standard normal distribution (z-distribution) is indeed 1.645.

Marketing Managers for a Toy Store Located in Two Separate