Two random variables x and y are independent if the value of x does not affect the value of y. If the variables are not independent, they are dependent. A new random variable can be formed by finding the sum or difference of random variables. If a random variable x has mean μx and a random variable y has mean μy then the means of the sum and difference of the variables are given by the following equations. μx+y=μx+μy μx−y=μx−μy The distribution of a test's scores for college-bound male seniors has a mean of 1528 and a standard deviation of 319. The distribution of a test's scores for college-bound female seniors has a mean of 1498 and a standard deviation of 304. One male and one female are randomly selected. Assume their scores are independent. What is the average sum of their scores? What is the average difference of their scores?