Mann-Whitney: Change the rank sum used for Wilcoxon W

diff --git a/src/language/stats/mann-whitney.c b/src/language/stats/mann-whitney.c
index b837177b57a557580860a08d0069257d697f7cac..94cb1ceb60b42efef44b0d96e3206eeea30f2cf2 100644 (file)
--- a/src/language/stats/mann-whitney.c
+++ b/src/language/stats/mann-whitney.c
@@ -121,11 +121,11 @@ mann_whitney_execute (const struct dataset *ds,
        mwv->u += mwv->n[0] * (mwv->n[0] + 1) / 2.0;
        mwv->u -= mwv->rank_sum[0];
 
-       mwv->w = mwv->rank_sum[0];
+       mwv->w = mwv->rank_sum[1];
        if ( mwv->u > mwv->n[0] * mwv->n[1] / 2.0)
          {
            mwv->u =  mwv->n[0] * mwv->n[1] - mwv->u;
-           mwv->w = mwv->rank_sum[1];
+           mwv->w = mwv->rank_sum[0];
          }
        mwv->z = mwv->u - mwv->n[0] * mwv->n[1] / 2.0;
        n = mwv->n[0] + mwv->n[1];