Chi-square test for Goodness of fit.
Advertisers need to know which age groups are probable 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 α = .01, does this sample contradict the assumption that readership is uniformly distributed among these six age groups? (See J. Paul Peter and Jerry C. Olson, Consumer Behaviour and Marketing.
Strategy, 9th ed. [McGraw-Hill, 2004], p. 300.) Cosmo
|
Purchase Age
|
Units Sold
|
|
18 - 24
|
38
|
|
25 - 34
|
28
|
|
35 - 44
|
19
|
|
45 - 54
|
16
|
|
55 - 64
|
10
|
|
65 +
|
9
|
|
Total
|
120
|
(a) Build a bar chart and describe it.
(b) Compute expected frequencies for each class.
(c) Execute the chi-square test for a uniform distribution. At α = .01, does this sample contradict the assumption that readership is uniformly distributed?