MA 220
E. Lee
Exercise 3
1. A manufacturer wishes to compare the wearing qualities of two types of automobile tires,
Aand B. For the comparison, a tire of type Aand one of type Bare randomly assigned
and mounted on the rear wheels of each of five automobiles. The automobiles are then
operated for a specified number of miles, and the amount of wear is recorded for each
tire. These measurements appear in the table. Do the data present sufficient evidence
to indicate a difference in the average wear for the two tire types? Test with α=.05.
Automobile Tire ATire B
1 10.6 10.2
2 9.8 9.4
3 12.3 11.8
4 9.7 9.1
5 8.8 8.3
¯yA= 10.24,¯yB= 9.76, sA= 1.316, sB= 1.328, s2
p= 1.748
