In a study of heart surgery, one issue was the effect of drugscalled beta-blockers on the pulse rate of patients during surgery.The available subjects were divided at random into two groups of 30patients each. One group received a beta-blocker; the other, aplacebo. The pulse rate of each patient at a critical point duringthe operation was recorded. The treatment group had mean 65.2 andstandard deviation 7.8. For the control group, the mean was 70.3and the standard deviation was 8.3.
(a) Do beta-blockers reduce the pulse rate at the 5% level? Atthe 1% level? Carry out a complete test.
(b) Give a 99% confidence interval for the difference in meanpulse rates.
