Data commit

Task/Cumulative-standard-deviation/CoffeeScript/cumulative-standard-deviation.coffee

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+class StandardDeviation
+    constructor: ->
+        @sum = 0
+        @sumOfSquares = 0
+        @values = 0
+        @deviation = 0
+
+    include: ( n ) ->
+        @values += 1
+        @sum += n
+        @sumOfSquares += n * n
+        mean = @sum / @values
+        mean *= mean
+        @deviation = Math.sqrt @sumOfSquares / @values - mean
+
+dev = new StandardDeviation
+values = [ 2, 4, 4, 4, 5, 5, 7, 9 ]
+tmp = []
+
+for value in values
+    tmp.push value
+    dev.include value
+    console.log """
+        Values: #{ tmp }
+        Standard deviation: #{ dev.deviation }
+
+    """