Data commit

Task/Cumulative-standard-deviation/MiniScript/cumulative-standard-deviation.mini

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+StdDeviator = {}
+StdDeviator.count = 0
+StdDeviator.sum = 0
+StdDeviator.sumOfSquares = 0
+
+StdDeviator.add = function(x)
+    self.count = self.count + 1
+    self.sum = self.sum + x
+    self.sumOfSquares = self.sumOfSquares + x*x
+end function
+
+StdDeviator.stddev = function()
+    m = self.sum / self.count
+    return sqrt(self.sumOfSquares / self.count - m*m)
+end function
+
+sd = new StdDeviator
+for x in [2, 4, 4, 4, 5, 5, 7, 9]
+    sd.add x
+end for
+print sd.stddev