A simple random sample of 64 men has a sample mean foot length of 27.5 cm. Assuming that the standard deviation of foot lengths for all men is 2 cm, obtain a 95% confidence interval for the mean foot...

A simple random sample of 64 men has a sample mean foot length of 27.5 cm. Assuming that the standard deviation of foot lengths for all men is 2 cm, obtain a 95% confidence interval for the mean foot length of all men. What is the upper limit of this interval, in centimetres?

(a) 27.5

(b) 27.0