A survey of 250 lobster fishermen found that they caatch an average of 32 pounds of lobster per ay with a standard deviation of four pounds.

A survey of 250 lobster fishermen found that they caatch an average of 32 pounds of lobster per ay with a standard deviation of four pounds. If a random sample of 30 lobster fishermen is selected what is the probability that their average catch is less than 31.5 pounds