Question:

A major razor blade manufacturer advertises that its twin-blade disposable razor “gets you lots more shaves” than any single-blade disposable razor on the market. A rival company that has been very successful in selling single-blade razors plans to test this claim. Independent random samples of eight single-blade users and eight twin-blade users are taken, and the number of shaves that each gets before indicating a preference to change blades is recorded. Do the data support the twin-blade manufacturer’s claim? α=.05. This is a t-tests independent samples.

Twin Blades Single Blades

8 10

17 6

9 3

11 7

15 13

10 14

6 5

12 7