In 1995, Cook County, Illinois (1.4 million households), conducted a study to determine

how far the head of household travels to work. A simple random sample of 2,518 households

was chosen and the occupants were interviewed. The survey found that the mean commuting

time for the head of households was 42.6 minutes and the standard deviation was 16.7

minutes. Does the study suggest that the true average commute time for Cook County, IL

in 1995 exceeds 42 minutes?

(a) Set up the hypotheses.

(b) Test your hypotheses with significance level of = 0:05.