12.1 A particular cell phone case is available in a choice of four different colors. A store sells all four colors.

To test the hypothesis that sales are equally divided among the four colors, a random sample of 100 purchases is identified.

a. If the resulting X2 value were 6.4, what conclusion would you reach when using a test with significance level 0.05?

b. What conclusion would be appropriate at significance level 0.01 if X2 5 15.3?

c. If there were six different covers rather than just four, what would you conclude if X2 5 13.7 and a test with a 5 0.05 was used?