.. _statistics-histogram_demo_cumulative:

statistics example code: histogram_demo_cumulative.py
=====================================================



.. plot:: /home/tcaswell/other_source/matplotlib/doc/mpl_examples/statistics/histogram_demo_cumulative.py

::

    """
    Demo of the histogram (hist) function used to plot a cumulative distribution.
    
    """
    import numpy as np
    import matplotlib.pyplot as plt
    from matplotlib import mlab
    
    
    mu = 200
    sigma = 25
    n_bins = 50
    x = mu + sigma*np.random.randn(10000)
    
    n, bins, patches = plt.hist(x, n_bins, normed=1,
                                histtype='step', cumulative=True)
    
    # Add a line showing the expected distribution.
    y = mlab.normpdf(bins, mu, sigma).cumsum()
    y /= y[-1]
    plt.plot(bins, y, 'k--', linewidth=1.5)
    
    # Overlay a reversed cumulative histogram.
    plt.hist(x, bins=bins, normed=1, histtype='step', cumulative=-1)
    
    plt.grid(True)
    plt.ylim(0, 1.05)
    plt.title('cumulative step')
    
    plt.show()
    

Keywords: python, matplotlib, pylab, example, codex (see :ref:`how-to-search-examples`)