An engineer is going to redesign an ejection seat for an airplane. The seat was designed for pilots weighing between 130 lb and 171 lb. The new population of pilots has normally distributed weights with a mean of 135lb and a standard deviation of 30.7 lb

a. If a pilot is randomlyselected, find the probability that his weight is between 130 lb and 171 lb.

The probability is approximately 0.4442. (Round to four decimal places asneeded.)

b. If 40 different pilots are randomlyselected, find the probability that their mean weight is between 130 lb and 171 lb.

The probability is approximately _________. (Round to four decimal places asneeded.)

I have answered a. What I need help with is b.

so far I have: z=130-135=-5/(30.7/square rt 40) = -24.27 but, this z value seem way to high.

I feel like i'm on the right track to solving this but that z value is high.