Use the pooled-variances t-test in comparing the sample means for the data of given Exercise. Is the conclusion consistent with the one reached in that exercise? Explain.
Exercise
Safety researchers, interested in determining whether the occupancy of a vehicle might be related to the speed at which the vehicle is driven, have observed the following speed (mph) measurements for two random samples of vehicles.
|
Driver alone
|
64
|
50
|
71
|
55
|
67
|
61
|
80
|
56
|
59
|
74
|
|
|
|
At least one passenger
|
44
|
52
|
54
|
48
|
69
|
67
|
54
|
57
|
58
|
51
|
62
|
67
|
a. What are the null and alternative hypotheses for this test?
b. Use ANOVA and the 0.025 level of significance in testing the null hypothesis identified in part (a).
c. For each sample, construct the 95% confidence interval for the population mean.