The chief chemist for a major gasoline production company claims that the regular unleaded gasoline produced by the company contains on average 4 ounces of a certain ingredient. The chemist further states that the distribution of this ingredient per gallon of regular unleaded gasoline is normal and has a standard deviation of 1.2 ounces. What is the probability of finding an average in excess of 4.3 ounces of this certain ingredient from 100 randomly inspected 1-gallon samples of regular unleaded gasoline?
A) .5987
B) .4013
C) .9938
D) .0062

Question

Quizplus · Accepted Answer

z = (4.3 − 4)/(1.2) + .3/.12 = 2.5
P(> 4.3) = 1.00 − .9938 = .0062

The Chief Chemist for a Major Gasoline Production Company Claims