A random sample of 36 mid-sized cars tested for the fuel consumption gave mean of 26.4 miles per gallon with the standard deviation of 2.3 miles per gallon.
a. Determine a 99% confidence interval for population mean, µ.
b. Assume the confidence interval obtained in part a is too wide. How can the width of this interval be reduced? Explain all possible alternatives. Which alternative is the best and why?