4. Gasoline prices reached record high levels in 16 states during 2003 (The Wall Street Journal, March 7, 2003). Two of the affected states were California and Florida. The American Automobile Association reported a sample mean price of $2.04 per gallon in California and a sample mean price of $1.72 per gallon in Florida. Use a sample size of 40 for the California data and a sample size of 35 for the Florida data. Assume that prior studies indicate a population standard deviation of .10 in California and .08 in Florida are reasonable.

a. What is a point estimate of the difference between the population mean prices per gallon in California and Florida?

b. At 95% confidence, what is the margin of error?

c. What is the 95% confidence interval estimate of the difference between the population mean prices per gallon in the two states?