HELP NEEDED ANSWERING THIS QUESTION!!!!!

Question

I AM LOST BECAUSE I'M NOT A HUGE FAN OF STATISTICS

 

An engineer is going to redesign an ejection seat for an airplane. The seat was designed for pilots weighing between 140 lb and 201 lb. The new population of pilots has normally distributed weights with a mean of 148 lb and a standard deviation of 29.4 lb.

a. If a pilot is randomly selected, find the probability that his weight is between 140 lb and 201 lb.

The probability is approximately ? . (Round to four decimal places as needed.)

Answer 1

Diane,

        First you calculate Z for each or the end points (140 and 201)

 

Z1=(140-148)/29.4=-.2721 i.e. this point is to the left of the mean about a quarter of a standard deviation 

 

Z2=(201-148)/29.4=1.803 i.e. this point is to the right of the mean about 1.8 standard deviations 

 

From a table of area under the normal curve we find the probability the Z lies between Z1 and Z2 is .5715. You can also calculate this using Excel or the various TI calculators.

 

Hope this helps

Jim