Question

According to the Air Transport Association of America, the average operating cost of an MD-80 jet airliner is $2,087 per hour. Suppose the operating costs of an MD-80 jet airliner are normally distributed with a standard deviation of $160 per hour.

(Round the value of z to 2 decimal places. Round your answers to 2 decimal places.)

(a) At what operating cost would only 20% of the operating costs be less? $enter the dollar amount at which only 20% of the operating costs would be less (b) At what operating cost would 65% of the operating costs be more? $enter the dollar amount at which 65% of the operating costs would be more (c) What operating cost would be more than 85% of operating costs? $enter the dollar amount that would be more than 85% of operating costs

Answer 1

Pageno AnSwed Given thout Population mean th= 2087 per hour Population sd = 160 per hour a d=20% At 2=0.20 in left tail from z table zd=-0.84 Operating Coşt x = ll-ZdXc -2087-0.84X160 2087 -134.4 = $1952.6 which is only 20% of the operating cost would be less b) 1-d=65% x=35% in left tail from a table Z2 = -0.39 lx = Mazaxa = 2087 -0.39 X 160

Pagenold - = 2087-62.4 = 2024.6 = $20246 which 65% of the operating Cost would be more Id=85% L=15% in right tail from a table Zd=1.04 operating cost X=ll + za xo = 2087 +1.04 x 160 = 2087 +1664 -$2,25 3.4 $2,253.4 would be more than 85%. of operating Coşi. t