A car manufacturer claims that its vehicles average at least 28 miles

A car manufacturer claims that its vehicles average at least 28 miles per gallon. Suppose, in fact, the cars only get 26.5 miles per gallon on average, with a population variance of 1. For an appropriate hypothesis test at a .975 confidence level, what is the power of a test of the company’s claim using a sample size of 4 cars?

a. .1492              b. .4658           c. .6543            d. .8508            e. .9236

Suppose amongst all the families on a Caribbean Cruise, the population variance of the number of children per family is 4. If we were to take a sample of 10 families, then the probability is .9 that the sample variance is less than ___. (Hint: Use the χ2 distribution.)

a. 6.53                b. 9.45                  c. 14.7               d. 16.2                  e. 17.8