Data commit

Task/Statistics-Basic/Elixir/statistics-basic.elixir

@@ -0,0 +1,27 @@
+defmodule Statistics do
+  def basic(n) do
+    {sum, sum2, hist} = generate(n)
+    mean = sum / n
+    stddev = :math.sqrt(sum2 / n - mean*mean)
+
+    IO.puts "size:   #{n}"
+    IO.puts "mean:   #{mean}"
+    IO.puts "stddev: #{stddev}"
+    Enum.each(0..9, fn i ->
+      :io.fwrite "~.1f:~s~n", [0.1*i, String.duplicate("=", trunc(500 * hist[i] / n))]
+    end)
+    IO.puts ""
+  end
+
+  defp generate(n) do
+    hist = for i <- 0..9, into: %{}, do: {i,0}
+    Enum.reduce(1..n, {0, 0, hist}, fn _,{sum, sum2, h} ->
+      r = :rand.uniform
+      {sum+r, sum2+r*r, Map.update!(h, trunc(10*r), &(&1+1))}
+    end)
+  end
+end
+
+Enum.each([100,1000,10000], fn n ->
+  Statistics.basic(n)
+end)