Fix robust distribution stats

src/x/__tests__/xRobustDistributionStats.test.ts

@@ -128,3 +128,28 @@ test('typed array', () => {
     xRobustDistributionStats(data),
   );
 });
+
+test('more complex case with multiple outliers', () => {
+  const data = [
+    1050, 1052, 1052, 1052, 1053, 1055, 1055, 1055, 1055, 1056, 1056, 1056,
+    1056, 1056, 1056, 1056, 1056, 1056, 1056, 1057, 1057, 1057, 1057, 1057,
+    1057, 1057, 1057, 1057, 1057, 1058, 1058, 1058, 1059, 1065, 1072, 1074,
+  ];
+
+  expect(xRobustDistributionStats(data)).toStrictEqual({
+    min: 1050,
+    q1: 1055.75,
+    median: 1056,
+    q3: 1057,
+    max: 1074,
+    lowerWhisker: 1053.875,
+    upperWhisker: 1058.875,
+    minWhisker: 1055,
+    maxWhisker: 1058,
+    iqr: 1.25,
+    outliers: [1050, 1052, 1052, 1052, 1053, 1059, 1065, 1072, 1074],
+    mean: 1056.4444444444443,
+    sd: 0.8915558282417289,
+    nb: 27,
+  });
+});

src/x/xDistributionStats.ts

@@ -20,10 +20,11 @@ export interface XDistributionStats extends XBoxPlotWithOutliers {
  * @returns q1, median, q3, min, max.
  */
 export function xDistributionStats(array: NumberArray): XDistributionStats {
+  const mean = xMean(array);
   return {
     ...xBoxPlotWithOutliers(array),
-    mean: xMean(array),
-    sd: xStandardDeviation(array),
+    mean,
+    sd: xStandardDeviation(array, { mean }),
     nb: array.length,
   };
 }

src/x/xRobustDistributionStats.ts

@@ -41,16 +41,17 @@ export function xRobustDistributionStats(
     filteredArray = new Float64Array(array.length - boxPlot.outliers.length);
     let j = 0;
     for (const element of array) {
-      if (element >= boxPlot.min && element <= boxPlot.max) {
+      if (element >= boxPlot.lowerWhisker && element <= boxPlot.upperWhisker) {
         filteredArray[j++] = element;
       }
     }
   }
 
+  const mean = xMean(filteredArray);
   return {
     ...boxPlot,
-    mean: xMean(filteredArray),
-    sd: xStandardDeviation(filteredArray),
+    mean,
+    sd: xStandardDeviation(filteredArray, { mean }),
     nb: filteredArray.length,
   };
 }