In Exercise 2.4, we presented the annual 2010 premium for a male, licensed for 6-8 years, who drives a Honda Accord 12,600 to 15,000 miles per year and has no violations or accidents.

a. Why would you expect these pairs of observations to be dependent?
b. Do the data provide sufficient evidence to indicate that there is a difference in the average annual premiums between GEICO and 21st Century insurance? Test using α = .01.
c. Find the approximate p-value for the test and interpret its value.
d. Find a 99% confidence interval for the difference in the average annual premiums for GEICO and 21st Century insurance.
e. Can we use the information in the table to make valid comparisons between GEICO and 21st Century insurance throughout the United States? Why or why not?

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City GEICO (S) Long Beach Pomona San Bernardino Moreno Valley 2780 2411 2261 2263 21st Century (S) 2352 2462 2284 2520