8.30 Average temperature in the United States Refer to the previous exercise. For the years 1895 to 2016 (a sample of 122 observations), the mean March monthly average temperature in the United States is 41.699°F with a standard deviation of 2.948°F.

a. Find the point estimate of the monthly average temperature for March in the United States and show that its standard error is 0.267.

b. The 95% confidence interval is 41.170 to 42.227.

Explain what “95% confidence” means for this interval.

c. Compared to the interval for Florida, is there enough evidence of a difference between the means? Explain.