Nonparametric Methods in Statistics with SAS Applications

52 HYPOTHESES TESTING FOR SEVERAL SAMPLES

Student Month 1 Month 2 Month 3 Month 4

1 2 4 3 4

2 0 1 3 4

3 4 5 4 7

4 3 3 4 3

5 0 0 1 3

6 4 3 5 5

7 5 5 4 2

Exercise 2.2 A TV company is studying the ways its customers prefer to be con-

tacted. Three methods of contact are under investigation: sending a letter in the mail,

calling on the residential phone, or sending a text message to the cell phone. Eight

customers are available for the study. They are contacted by the customer service

department by all three methods (in randomly chosen order). For every contact they

assess how happy they are with the service by estimating the probability of staying

with the