Suppose the mean length of time that a caller is placed on hold when telephoning a customer service center is 23.8 seconds, with standard deviation 4.6 seconds. Find the probability that the mean length of time on hold in a sample of 1,200 calls will be within 0.5 second of the population mean.

Answer 1

0.5 is 0.1087σ from the mean.
Now run that through your standard formulas.

Answer 2

please oobleck help us complete the standard formulas to arrive at the final answer.