You are the product manager for brand 4 in a large food company. The company president has complained that a competing brand, called brand 2, has higher average sales. The data services group has stored the latest product sales (saleb2 and saleb4) and price data (apriceb2 and apriceb4) in a file named Storet described in Chapter 10 appendix.
a. Based on a statistical hypothesis test, does the president have strong evidence to support her complaint? Show all statistical work and reasoning.
b. After analyzing the data, you note that a large outlier of value 971 is contained in the sample for brand 2. Repeat part a with this extreme observation removed. What do you now conclude about the president's complaint?