An airline flies the same route at the same time each day. The flight time varies according to a Normal distribution with unknown mean and standard deviation. On 15% of days, the flight takes more than an hour. On 3% of days, the flight lasts 75 minutes or more. Use this information to determine the mean and standard deviation of the flight time distribution.

Question

campbell_st · Answer

you need a table of z scores, and look them up

anonymous · Answer

how do i do it on the calculator though?

campbell_st · Answer

well the formula for calculating a z score is 

$$z = \frac{x - \mu}{\sigma}$$

use the tables to look up the z score that matches 97% and the z score that matches  85%

then you'll need to solve the 2 equations simulataneously is my guess