Question: The population of male industrial workers in London who have never experienced a major coronary event has a mean systolic blood pressure 136 mm Hg and mean diastolic blood pressure 84 mm Hg. You might be interested in determining whether these values are the same as those for the population of industrial workers who have suffered a coronary event.

(a) A sample of 86 workers who have experienced a major coronary event has mean systolic blood pressure = 143 mm Hg and standard deviation = 24.4 mm Hg. Test the null hypothesis that the mean systolic blood pressure for the population of industrial workers who have experienced such an event is identical to the mean for the workers who have not, using a two-sided test at the 0.05 level of significance.

(b) The same sample of men has mean diastolic blood pressure = 87 mm Hg and standard deviation = 16.0 mm Hg. Test the null hypothesis that the mean diastolic blood pressure for the population of workers who have experienced a major coronary event is identical to the mean for the workers who have not.

(c) How do the two groups of workers compare?