change method to compute std for nonparametric

Salmon-Brain · May 13, 2022 · eb4b9b9 · eb4b9b9
1 parent c18a7b6
commit eb4b9b9
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/ruleofthumb/src/main/scala/ai/salmonbrain/ruleofthumb/MannWhitneyTest.scala b/ruleofthumb/src/main/scala/ai/salmonbrain/ruleofthumb/MannWhitneyTest.scala
@@ -45,7 +45,9 @@ object MannWhitneyTest extends BaseStatTest {
         val uStatistic = mannWhitneyUTest.mannWhitneyU(control, treatment)
         val pValue = mannWhitneyUTest.mannWhitneyUTest(control, treatment)
 
-        val std = math.sqrt(treatmentMedianVariance + controlMedianVariance)
+        val std = math.sqrt(
+          controlMedianVariance / control.length + treatmentMedianVariance / treatment.length
+        )
         val size = math.max(control.length, treatment.length)
 
         val ci = CI(