The data below represent the number of hours of pain relief provided by two brands of headache tablets administered to 42 subjects. These subjects were randomly divided into two groups and each group...

The data below represent the number of hours of pain relief provided by two brands of headache tablets administered to 42 subjects. These subjects were randomly divided into two groups and each group was treated with different brand. Use z-test at 0.05 level of significance to if significant difference exists between the average number of hours of pain relief provided by the two brands of tablet.
Brand ABrand B
53
52
74
65
53
77
86
45
34
71
82
53
33
24
18
47
65
56
27
65
45