Painkiller is the medicine that suppresses pains, like headache. Two types of new painkillers, say A and B are going to be in market. Both painkillers have very little side effects, if taken according to recommended daily dosage. The effectiveness of painkiller can be evaluated by the effective duration in which the pain is fully suppressed. Two groups of volunteers are employed to test the effectiveness of new drug, one group is for A and another group is for B. Each and every group member took a prescribed dosage and effective durations (in hours) are recorded. The result is as follows:
Group A (for painkiller A).
Member 1 2 3 4 5 6 7 8 9 10 11 12
Hours 7.5 6.8 5.9 8.4 8.0 7.2 7.7 8.6 7.1 6.4 8.2 7.7
Group B (For painkiller B)
Member 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Hours 3.8 10.4 11.2 5.1 4.1 12.8 13.5 8.3 6.2 2.8 15.9 10.8 9.4 20.8 3.9
Both painkillers will soon be available to the general public, given above testing data, and using appropriate statistical analysis, supposing that effective duration is normally distributed, can you conclude the following to general public:
a) Painkiller B has longer average effective duration than that of painkiller A?
b) Painkiller B has larger variation in effective duration than that of painkiller A?