1. A contractor assumes that the idle time for construction workers is not expected to exceed 75 minutes. A random sample of 25 construction workers was taken and the mean idle time was found to be 84...

1.
A contractor assumes that the idle time for construction workers is not expected to exceed 75 minutes. A random sample of 25 construction workers was taken and the mean idle time was found to be 84 minutes per day with a sample standard deviation of 20 minutes. Assume that the population is approximately normally distributed; use a 5% level of significance to test the contractor’s assumption.