An auto manufacturer claims that the variance of the gas mileages in a certain vehicle model is 1.0. A random sample of 25 vehicles has a variance of 1.65. At α = 0.05, is there enough evidence to reject the manufacturer’s claim?
(a) Identify the claim and state H0 and Ha,
(b) Find the critical value(s) and identify the rejection region(s),
(c) Find the standardized test statistic X2,
(d) Decide whether to reject or fail to reject the null hypothesis,
(e) Interpret the decision in the context of the original claim. Assume the population is normally distributed. |

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