code: def draw_histogram():
      
  
      mu, sigma = 100, 15
      x = mu + sigma * numpy.random.randn(10000)
      fig = pyplot.figure()
      ax = fig.add_subplot(111)
      n, bins, patches = ax.hist(x, 50, normed=1, facecolor='green', alpha=0.75)
  
      ax.set_xlabel('Random number generated')
      ax.set_ylabel('Probability')
      ax.set_xlim(40, 160)
      ax.set_ylim(0, 0.03)
      ax.grid(True)
  
      pyplot.savefig(histogram_filename)
docs: Uses sample code from http://matplotlib.org/1.2.1/examples/api/histogram_demo.html