A typing instructor wondered whether a new method of instruction would result in a change in the mean typing speed of students. The old method produced a mean of 64 words per minute. The results (words per minute) for 38 students using the new method were as follows:
|
56
|
60
|
60
|
76
|
60
|
59
|
41
|
66
|
67
|
33
|
55
|
43
|
61
|
|
71
|
73
|
60
|
56
|
77
|
43
|
58
|
65
|
67
|
71
|
56
|
48
|
90
|
|
82
|
46
|
68
|
36
|
27
|
52
|
64
|
54
|
49
|
69
|
46
|
68
|
|
Note that Σx = 2233 and Σx2 = 138,053. At the 5% level of significance, can the instructor conclude that the new mean is different from 64?