The city fuel economy of a 2009 Toyota 4Runner 2WD 6 cylinder 4 L automatic 5?speed using regular gas is a normally distributed random variable with a range 22 MPG to 25 MPG. (a) Estimate the standard deviation using Method 3 (the Empirical Rule for a normal distribution). (Round your answer to 2 decimal places.) Standard deviation (b) What sample size is needed to estimate the mean with 95 percent confidence and an error of ± 0.25 MPG? (Round your answer to the nearest whole number.) Sample size