A random sample of 16 mid-sized cars tested for fuel consumption gave a mean of 26.4 kilometers per litre with a standard deviation of 2.3 kilometers per litre.
A. Assuming that the kilometers per litre given by all mid-sized cars have a normal distribution, find a 99% confidence interval for the population mean μ.
B. Suppose the confidence interval obtained in (a) is too wide. How can the width of this interval be reduced? Describe all possible alternatives. Which alternative is the best and why?