Question 181078: A sample of 25 concession stand purchases at the October 22 matinee of Bride of Chucky showed
a 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 α = .05, is there a difference
in variances? Show all steps clearly, including an illustration of the decision rule.
Question out of Textbook Applied Statistics by Doane and Seward, 10.56 chapter 10. ISBN-13 978-0-07-296693-0
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A sample of 25 concession stand purchases at the October 22 matinee of Bride of Chucky showed a 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 α = .05, is there a difference in variances? Show all steps clearly, including an illustration of the decision rule
--------------------
Ho: variance matinee = variance evening
Ha: they are not equal
Run 2-Sample F-Test to get:
Test Stat: F = 1.9915...
p-value: 0.09811...
df numerator = 24 = df denominator
Critical Value: F(right) = 2.23 ; F(left)= 1/2.33 = 0.448..
--------
Conclusion: Since p-value is greater than 5%, Fail to reject Ho.
The variances are not statistically different.
=================================================
Cheers,
Stan H.
|
|
|
