STA2201s01 Assignment Eight

Quiz or hand in Thursday March 22

A market is dominated by five major brands (A, B, C, D, and E), and a large number of minor brands. A market research organization selects a sample of consumers each quarter (a different independent sample or "wave" each quarter), and asks how many items of each brand the consumer has purchased in the last year. The data file market.dat contains data from two waves. It has n1+n2 rows, and seven columns. The first column is wave (1 or 2). Column 2 is number of items of Brand A purchased, column 3 is number of items of Brand B purchased, ..., column 6 is number of items of Brand E purchased, and column 7 is number of items of Brand Other purchased.

1. Make a table showing the mean number of items purchased for each brand, in each of the two waves. Your table will have 12 sample means.
2. Create a new variable, the total number of items purchased (all brands combined). Did the mean of this variable change between the two waves? Answer yes or no; use alpha=0.05.
3. Do a similar test simultaneously for the 6 dependent variables. Again using alpha=0.05, what do you conclude?