Quiz 9: Hypothesis Testing & Confidence Intervals for Mean Sales in N & S Regions, Quizzes of Introduction to Business Management

Download Quiz 9: Hypothesis Testing & Confidence Intervals for Mean Sales in N & S Regions and more Quizzes Introduction to Business Management in PDF only on Docsity! MS 251: Statistical Analysis for Business Decisions Spring 2000 Quiz 9 1. A marketing research firm wants to determine if mean sales in its northern region are greater than mean sales in its southern region. A random sample of 40 was taken in the northern region and 22 in the southern region. The sample mean and standard deviation for the northern region were 500 and 80, respectively. For the southern region, the sample mean and standard deviation were 450 and 60, respectively. Perform a hypothesis test to see if there is enough evidence at the alpha=.05 significance level to infer that the mean sales are greater in the northern region. 2. Using the information from problem 1, calculate a 95% confidence interval for the difference of the population means. 3. Given a choice between observational data and experimental data, which would you prefer? Why?