title: Plot a histogram such that bar heights sum to 1 (probability)
body: <p>I'd like to plot a normalized histogram from a vector using <code>matplotlib</code>.  I tried the following:</p>
  <pre><code>plt.hist(myarray, normed=True)
  </code></pre>
  <p>as well as:</p>
  <pre><code>plt.hist(myarray, normed=1)
  </code></pre>
  <p>but neither option produces a y-axis from [0, 1] such that the bar heights of the histogram sum to 1.</p>