In exercises that call for two-sample procedures, you may use either of the two approximations for the degrees of freedom that we have discussed: the value given by your software or the smaller of and . Be sure to state clearly which approximation you have used.
7.62 When is 52 weeks not equal to a year?
Refer to the previous exercise. The researchers also had 60 marketing students read an announcement about a construction project. The expected duration was either one year or 52 weeks. Each student was then asked to state the earliest and latest completion date.
| Group | |||
|---|---|---|---|
| 52 weeks | 30 | 84.1 | 55.8 |
| 1 year | 30 | 139.6 | 73.1 |
Test that the average interval is the same for the two groups using the significance level. Report the test statistic, the degrees of freedom, and the -value. Give a short summary of your conclusion.