Two Population Means with Known Standard Deviations · Exercise 14
Some manufacturers claim that non-hybrid sedan cars have a lower mean miles-per-gallon (mpg) than hybrid ones. Suppose that consumers test 21 hybrid sedans and get a mean of 31 mpg with a standard deviation of seven mpg. Thirty-one non-hybrid sedans get a mean of 22 mpg with a standard deviation of four mpg. Suppose that the population standard deviations are known to be six and three, respectively. Conduct a hypothesis test to evaluate the manufacturers claim.
This is an open-ended exercise: its source gives no single answer.
OpenStax, Introductory Business Statistics 2e · §10.5 Two Population Means with Known Standard Deviations · Exercise 14
No hints for this one.
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