title: How to get the area under a histogram in python
body: <p>I have been plotting a histogram. My code looks like this:</p>
  
  <pre><code>x0=-15000
  x1=15000
  b=np.arange(x0,x1,(x1-x0)/250.)
  
  plt.plot(b[0:-1], plt.hist(non_zeros(-e[0]), bins=b, normed=1, visible=0)[0], color = "k", label=r'$\gamma$ = 1.0')
  </code></pre>
  
  <p>I normed the histogram so the area under the curve is equal to 1.  e[0] is just some data i take in from a document. </p>
  
  <p>What i want now is to double check that the are under the histogram is equal to one. How can this be done?</p>