39. FILE (Use Excel) Barbara Dwyer, the manager at Lux Hotel, makes every effort to ensure that customers attempting to make phone reservations do not have to wait too long to speak with a reservation specialist. Since the hotel accepts phone reservations 24 hours a day, Barbara is especially interested in maintaining consistency in service. Barbara wants to determine if the variance of wait time in the early morning shift differs from that in the late morning shift. She uses the following independently drawn samples of wait time for phone reservations for both shifts for the analysis.

The data can be found on the text website and are labeled Wait Times. Assume that wait times are normally distributed.

Shift Wait Time (in seconds)
Early Morning Shift: 12:00 am-
6:00 am 67 48 52 7 1 83 59 49 66 57 68 6 0 6 82 6 3 64 83 37 41 60 41 87 53 66 69 Late Morning Shift: 6:00 am-
12:00 pm 98 100 122 108 100 123 102 90 125 121 120 128 123 94 1 2 8 113 116 104 96 111 107 105 113 106

a. Specify the appropriate hypotheses to test if the variance o f wa i t t im e in th e early mo rnin g shift differs from th a t in the late morning shift.

b. Use Excel's F.TEST function to conduct the test at the 1%
level of significance.

c. Does the variance o f wait t ime in the early morning shift differ from that in the late afternoon shift?