Question: The weight of bags “checked in” is normal, with a mean of 30 pounds and a standard deviation of 9 pounds.

a) What is the probability that a randomly selected bag will weigh more than 48 pounds?

b) What is the probability that the total weight of 4 bags will be more than 192 pounds?

c) Find the probability that a sample of 81 bags will average more than 32 pounds.

d) If a sample of 36 bags showed the mean to be 33 pounds, can you conclude that the average weight has changed? (use alpha = 0.05)