Lib.median(): reuse existing Lib.interp()

Author: antoinerg

src/lib/stats.js

@@ -78,16 +78,9 @@ exports.stdev = function(data, len, mean) {
  * median of a finite set of numbers
  * reference page: https://en.wikipedia.org/wiki/Median#Finite_set_of_numbers
 **/
-exports.median = function(data, len) {
-    if(!len) len = exports.len(data);
+exports.median = function(data) {
     var b = data.slice().sort();
-    if(len % 2 === 0) {
-        // If even
-        return (b[len / 2 - 1] + b[len / 2]) / 2;
-    } else {
-        // If odd
-        return b[(len - 1) / 2];
-    }
+    return exports.interp(b, 0.5);
 };
 
 /**

test/jasmine/tests/lib_test.js

@@ -178,13 +178,13 @@ describe('Test lib.js:', function() {
 
     describe('median() should', function() {
         it('return the middle value exactly for odd number of observations:', function() {
-            var input = [1, 3, 3, 6, 7, 8, 9];
+            var input = [1, 8, 9, 2, 7, 6, 3];
             var res = Lib.median(input);
             expect(res).toEqual(6);
         });
 
         it('return the mean of the two middle values for even number of observations', function() {
-            var input = [1, 2, 3, 4, 5, 6, 8, 9];
+            var input = [4, 3, 2, 1, 5, 6, 8, 9];
             var res = Lib.median(input);
             expect(res).toEqual(4.5);
         });