Q1) Sample of 25 concession stand purchases at October 22 matinee of Bride of Chucky showed a mean purchase of $5.29 with standard deviation of $3.02. For October 26 evening showing of the same movie, for sample of 25 purchases mean was $5.12 with standard deviation of $2.14. Means appear to be very close, but not variances. At α = .05, is there a difference in variances? Illustrate all steps clearly, including illustration of the decision rule.
Q2) In bumper test, 3 types of autos were deliberately crashed into barrier at 5 mph, and resulting damage (in dollars) was estimated. 5 test vehicles of each type were crashed, with the results shown below.
Research question: Are mean crash damages the same for these three vehicles?
Crash Damage ($)
|
Goliath
|
Varmint
|
Weasel
|
|
1,600
|
1,290
|
1,090
|
|
760
|
1,400
|
2,100
|
|
880
|
1,390
|
1,830
|
|
1,950
|
1,850
|
1,250
|
|
1,220
|
950
|
1,920
|