The following is a set of data from a sample of n = 11 items: X 7 5 8 3 6 10 12 4 9 15 18 Y 21 15 24 9 18 30 36 12 27 45 54 a. Compute the covariance. b. Compute the coefficient of correlation. c. How strong is the relationship between X and Y? Explain.