Refer to Exercise 6.7. a. Find the covariance of the random variables x and y. b. Find

Question:

Refer to Exercise 6.7.
a. Find the covariance of the random variables x and y.
b. Find the coefficient of correlation r for x and y.

Data from Exercise 6.7

A special delivery truck travels from point A to point B and back over the same route each day. There are three traffic lights on this route. Let X be the number of red lights the truck encounters on the way to delivery point B and let Y be the number of red lights the truck encounters on the way back to delivery point A. A traffic engineer has determined the joint probability distribution of X and Y shown in the table.