Acollege bookseller makes calls at the offices of professors and forms the impression that professors are more likely to be away from their offices on friday than any other working day. a review of the records of calls, 20% of which are on fridays, indicates that for 18% of friday calls, the professor is away from the office, while this occurs for only 11% of calls on every other working day. define the random variables as follows: x = 1if call is made on fridayx = 0, otherwisey = 1if professor is away from officey = 0, otherwise(a)find the joint probability distribution of x and y. (b)find the conditional probability distribution of y, given x = 0. (c)find the marginal probability distributions of x and y. (d)find and interpret the covariance between x and y.