You want to know how the commuting time of your employees compare to Departments competing for the same staff, so you get some survey data on average commuting times for36 randomly selected people in your line of business.

You find that the mean commuting time is 75 minutes, with a standard deviation of 45. This will give you a standard error of7.5, because your sample size is 36, the square root of which is 6(calculate it for yourself).

a) Based on this, calculate a 95 percent Confidence Interval for the mean commuting time. (Remember, the C.I. is calculated by adding and subtracting from the observed sample mean the product of the standard error and the appropriate Z value.)