The manufacturer of a new compact car claims the miles per gallon (mpg) for the gasoline consumption is mound-shaped and symmetric with a mean of 24.6 mpg and a standard deviation of 11.2 mpg. If 30 such cars are tested, what is the probability the average mpg achieved by these 30 cars will be greater than 27?

Question

The manufacturer of a new compact car claims the miles per gallon (mpg) for the gasoline consumption is mound-shaped and symmetric with a mean of 24.6 mpg and a standard deviation of 11.2 mpg.  If 30 such cars are tested, what is the probability the average mpg achieved by these 30 cars will be greater than 27?

Reiny · Accepted Answer

Use this "magic" page http://davidmlane.com/hyperstat/z_table.html enter the mean and sd as you have them click on "above" and enter 27 you should get .4152

Jack · Answer

.0733