Carbon monoxide CO emissions for a certain kind of car vary

Carbon monoxide (CO) emissions for a certain kind of car vary with mean 2.322 g/mi and standard deviation 0.6 g/mi. A company has 7070 of these cars in its fleet. Let y overbary represent the mean CO level for the company\'s fleet.

a) What\'s the approximate model for the distribution of y over bar y?

Explain.

b) Estimate the probability that y over bar y is between 2.4 and 2.5

g/mi.

c) There is only a

1010%

chance that the fleet\'s mean CO level is greater than what value?

Solution