Question

A city planner working on bikeways designs a questionnaire to obtain information about local bicycle commuters. One of the questions asks how long it takes the rider to pedal from home to his or her destination. A sample of local bicycle commuters yields the following times, in minutes.

22	19	24	31	29	29	23	48
21	15	27	23	37	31	22	29
30	26	16	26	12	28

a. Graphical analyses of the data indicate that the data are roughly normally distributed but the time of 48 minutes may be an outlier. Remove this outlier and test at the 5% significance level, do the data provide sufficient evidence to show that the mean commuting time of all local biker less than the value of the outlier of 48 minutes. (Note: Remove the outlier before working on the test.)

b. Find a 90% confidence interval for the mean commuting time of all local bicycle commuters in the city. (Note: Remove the outlier first.)

Answer 1