The weight of eggs produced by u certain type of hen varies according to a distribution that is approximately normal with mean 6'5 grams and standard deviation 5 grams.
(a) What is the probability that a randomly selected from such a hen weighs more than 11.5 grams
(b) What is the probability that the average of a random sample of 25 eggs from such hens will be less than 5.8 grams ?