A sample of 25 concession stand purchases at the October 22 matinee of Bride of
ID: 2959783 • Letter: A
Question
A sample of 25 concession stand purchases at the October 22 matinee of Bride of Chucky showeda mean purchase of $5.29 with a standard deviation of $3.02. For the October 26 evening showing
of the same movie, for a sample of 25 purchases the mean was $5.12 with a standard deviation of
$2.14. The means appear to be very close, but not the variances. At a = .05, is there a difference
in variances? Show all steps clearly, including an illustration of the decision rule. (Data are from
a project by statistics students Kim Dyer, Amy Pease, and Lyndsey Smith.)
10.57 A ski company in Vail owns two ski shops, one on the west side and one on the
Explanation / Answer
The test hypothesis is Ho: s^2(matinee)=s^2(evening) Ha: s^2(matinee) is not equal to s^2(evening) ------------------------------- Two-tailed test with alpha = 0.05 ------------------------------ Test Statistic: F = (2.14)^2/(3.02)^2 = 0.502127 Critical Value: numerator df's = 24 ; denominator df's = 24 F = 2.27 ----------- Since the Test Statistic is less than the Critical Value, Fail to reject Ho. The variances for matinee and evening are statistically equivalent.