When a computer chip is examined to discover how many of the solder joints have become cracked, there is a probability of 0.12 that none of the joints are cracked, a probability of 0.43 that one of the joints is cracked, a probability of 0.28 that two of the joints are cracked, and a probability of 0.17 that three of the joints are cracked.
(a) What is the mean number of cracked joints in a computer chip?
(b) What is the standard deviation of the number of cracked joints in a computer chip?
(c) Suppose that two different chips are randomly selected. What are the mean and the standard deviation of the total number of cracked joints in the two chips combined?