Question

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.
oobleck
0.5 is 0.1087σ from the mean.
Now run that through your standard formulas.
daniel
please oobleck help us complete the standard formulas to arrive at the final answer.