Using the sample data in Exercise 10.57, construct and interpret the 95% confidence interval for the population mean. Is the hypothesized population mean ($817) within the interval? Given the presence or absence of the $817 value within the interval, is this consistent with the findings of the hypothesis test conducted in Exercise 10.57?
In exercise
According to the Insurance Information Institute, the mean annual expenditure for automobile insurance for U.S. motorists is $817. Suppose that a government official in North Carolina has surveyed a simple random sample of 80 residents of her state, and that their auto insurance expenditures for the most recent year are in data file XR10057. Based on these data, examine whether the mean annual auto insurance expenditure for motorists in North Carolina might be different from the $817 for the country as a whole. Identify and interpret the p-value for the test.