--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/javascript/d3/examples/qq/stats.js	Thu Apr 10 14:20:23 2014 +0200
@@ -0,0 +1,28 @@
+// Sample from a normal distribution with mean 0, stddev 1.
+function normal() {
+  var x = 0, y = 0, rds, c;
+  do {
+    x = Math.random() * 2 - 1;
+    y = Math.random() * 2 - 1;
+    rds = x * x + y * y;
+  } while (rds == 0 || rds > 1);
+  c = Math.sqrt(-2 * Math.log(rds) / rds); // Box-Muller transform
+  return x * c; // throw away extra sample y * c
+}
+
+// Simple 1D Gaussian (normal) distribution
+function normal1(mean, deviation) {
+  return function() {
+    return mean + deviation * normal();
+  };
+}
+
+// Gaussian Mixture Model (k=3) fit using E-M algorithm
+function normal3(dd) {
+  return function() {
+    var r = Math.random(),
+        i = r < dd[0][2] ? 0 : r < dd[0][2] + dd[1][2] ? 1 : 2,
+        d = dd[i];
+    return d[0] + Math.sqrt(d[1]) * normal();
+  }
+}