Association claims that the annual cost of medical care for dogs averages $102, with standard deviation of $28, and for cats averages $124, with a standard deviation of $33.
Question: (a) What is expected difference in the cost of medical care between a dog and a cat?
(b) what is standard deviation of the difference in the cost of medical care between a dog and a cat?
(c) if the difference in costs can be described by a normal modal, what is the probability that medical expenses are higher for someones' dog than for his cat?