A certain psychological test measures empathy and emotional intelligence. The score, S, of a randomly selected senior student at a large university has a mean of 123 and a standard deviation of 29. The score, F, of a randomly selected first-year student at a large university has a mean of 104 and a standard deviation of 34. Suppose we randomly select one senior student and one first-year student.

Calculate the mean of the difference D = S – F.

μD = 17.7482
μD = 19
μD = 44.6878
μD = 227