Picking melons Two stores sell watermelons. At the first store, the melons weigh an average of 22 pounds, with a standard deviation of 2.5 pounds. At the second store, the melons are smaller, with a...

Picking melons Two stores sell watermelons. At the first store, the melons weigh an average of 22 pounds, with a standard deviation of 2.5 pounds. At the second store, the melons are smaller, with a mean of 18 pounds and a standard deviation of 2 pounds. You select a melon at random at each store.

a) What’s the mean difference in weights of the melons?

 b) What’s the standard deviation of the difference in weights?

c) If a Normal model can be used to describe the difference in weights, what’s the probability that the melon you got at the first store is heavier?