The median response and its interval are calculated for Y of each treatment and the crossover difference between treatments, C. Let X(1), X(2),…, X(N) be the order statistic of samples X1, X2,…, XN. The median Xm is defined as:
The 100% confidence interval (CI) of Xm is defined as follows.
For N <= 20, the exact probability value is obtained from a Mann-Whitney U-distribution.
For N > 20, normal approximation is used:
where int(X) returns the largest integer less than or equal to X.