Question 3
A bank with a branch located in the commercial district of a city has developed an improved process for serving customers during the 12:00 to 13:00 peak lunch period. The waiting times, during this period, of all customers was recorded over a period of one week. The waiting times (in min) of 15 randomly-selected customers is given below.
|
4.21
|
5.55
|
3.02
|
5.13
|
4.77
|
|
2.34
|
3.54
|
3.20
|
4.50
|
6.10
|
|
0.38
|
5.12
|
6.46
|
6.19
|
3.79
|
Suppose that another bank located in a residential area is most concerned with the Friday evening hours from 5 to 7. A sample of the waiting times of 15 randomly-selected customers is given in the table below.
|
9.66
|
5.90
|
8.02
|
5.79
|
3.82
|
|
8.01
|
8.35
|
10.49
|
6.68
|
5.64
|
|
4.08
|
6.17
|
9.91
|
5.47
|
8.73
|
Conduct a full test, at the 5% level of significance, to establish whether there is a statistically significant difference between the population mean times in the two banks. (Assume that the samples are drawn from populations that are approximately normally distributed and that their variances are equal.)