Question

An engineer is going to redesign an ejection seat for an airplane. The seat was designed for pilots weighing between120 lb and 161 lb. The new population of pilots has normally distributed weights with a mean of 129 lb and a standard deviation of 34.1 lb.
a. If a pilot is randomly​ selected, find the probability that his weight is between 120 lb and 161 lb.
The probability is approximately 0.4290. ​(Round to four decimal places as​ needed.)
b. If 33 different pilots are randomly​ selected, find the probability that their mean weight is between 120 lb and 161 lb.
The probability is approximately nothing. ​(Round to four decimal places as​ needed.)

Answer 1

Refer Standard normal table/Z-table to find the probability or use excel formula "=NORM.S.DIST(0.94, TRUE)" & "=NORM.S.DIST(-0.26, TRUE)" to find the probability.

------------------------------------------------------------------------------------------------------------------------

Refer Standard normal table/Z-table to find the probability or use excel formula "=NORM.S.DIST(5.39, TRUE)" & "=NORM.S.DIST(-1.52, TRUE)" to find the probability.

------------------------------------------------------------------------------------------------------------------------