Question: Advertisers need to know which age groups are likely to see their ads. Purchasers of 120 copies of Cosmopolitan are shown by age group.

(a) Make a bar chart and describe it.

(b) Calculate expected frequencies for each class.

(c) Perform the chi-square test for a uniform distribution. At \(\alpha =\) .01, does this sample contradict the assumption that readership is uniformly distributed among these six age groups?

Purchaser Age Units Sold
18–24 38
25–34 28
35–44 19
45–54 16
55–64 10
65+ 9
Total 120