Posted by tone on .
16. Based on tests of the Chevrolet Cobalt, engineers have found that the miles per gallon in highway driving are normally distributed, with a mean of 32 miles per gallon and a standard deviation 3.5 miles per gallon

statistics 
PsyDAG,
What is your question?

statistics 
tone,
16. Based on tests of the Chevrolet Cobalt, engineers have found that the miles per gallon in highway driving are normally distributed, with a mean of 32 miles per gallon and a standard deviation 3.5 miles per gallon.
a) What is the probability that randomly selected Cobalt gets more than 34 miles per gallon?
The answer is approximately =0.017
b) Ten Cobalts are randomly selected and the miles per gallon for each car are recorded. What is the probability that the mean miles per gallon exceed 34 miles per gallon?
The final answer will be = 0.0351
c) Twenty Cobalts are randomly selected and the miles per gallon for each car are recorded, What is the probability that the mean miles per gallon exceeds 34 miles per gallon? Would this result be unusual? Explain.
The sample mean obtained is unusual.
17. Burger King's DriveThrough: Suppose that cars arrive at Burger King's drivethrough at the rate of 20 cars every hour between 12:00 noon and 1:00 PM. A random sample of 40 onehour time periods between 12:00 noon and 1:00 P.M. is selected and has 22.1 as the mean number of cars arriving. 
statistics 
Linz,
How did you find part a?