Question

An engineer is going to redesign an ejection seat for an airplane. The seat was designed for pilots weighing between 140 lb and 181 lb. The new population of pilots has normally distributed weights with a mean of 146 lb and a standard deviation of 28.9 lb.

A) If a pilot is randomly selected, find the probability that his weight is between 140 and 181 lb.

B) If 32 different pilots are randomly selected, find the probability that their mean weight is between 140 and 181 lb

Answer 1

A) Z = (score-mean)/SD

B) Z = (score-mean)/SEm

SEm = SD/√n

For both, find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions/probabilities related to the Z scores.

Answer 2

12