In Comment 4, we noted that we have K = 2K' - {n(n - 1)/2}, where K' = (number of concordant pairs), when there are neither tied X nor tied Y observations. Obtain the corresponding expression for the relationship between K and K' when there are no tied X pairs and a total of t (≠ 0) tied Y pairs (among the 
total Y pairs), and we use the Q∗ (8.17) counts of zero to deal with the tied Y pairs. How does this expression change if there are no tied Y pairs and t tied X pairs? Discuss the necessary changes in the expression relating K and K' when there are s (≠ 0) tied X pairs and t (≠ 0) tied Y pairs.