Question

Flight times 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 deter-
mine the mean and standard deviation of the flight
time distribution.

Answer 1

Mean = 41.588

Standard Deviation = 17.765

Explanation:

60 - N/D = 1.03643

75 - M/D

75 - (60 - 1.03643D)/D = 1.88079

15 + 1.03643D = 1.88079D

15 = 0.84436D

17.765 = D

D = 17.765

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

60 - M = 1.03643D

60 - 1.03643D = M

M = 60 - 1.03643(17.765)

M = 41.588