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 of less than 3.85 ounces of this certain ingredient from 64 randomly inspected 1-gallon samples of regular unleaded gasoline?
A) .1587
B) .8413
C) .1357
D) .8643

Question

Quizplus · Accepted Answer

z = (3.85 − 4)/(1.2/) = −.15/.15 = −1.0
p (< 3.85) = .1587

The Chief Chemist for a Major Gasoline Production Company Claims