from scipy.stats import beta import matplotlib.pyplot as plt fig, ax = plt.subplots(1, 1) # Calculate a few first moments: a, b = 2.31, 0.627 mean, var, skew, kurt = beta.stats(a, b, moments='mvsk') # Display the probability density function (``pdf``): x = np.linspace(beta.ppf(0.01, a, b), beta.ppf(0.99, a, b), 100) ax.plot(x, beta.pdf(x, a, b), 'r-', lw=5, alpha=0.6, label='beta pdf') # Alternatively, the distribution object can be called (as a function) # to fix the shape, location and scale parameters. This returns a "frozen" # RV object holding the given parameters fixed. # Freeze the distribution and display the frozen ``pdf``: rv = beta(a, b) ax.plot(x, rv.pdf(x), 'k-', lw=2, label='frozen pdf') # Check accuracy of ``cdf`` and ``ppf``: vals = beta.ppf([0.001, 0.5, 0.999], a, b) np.allclose([0.001, 0.5, 0.999], beta.cdf(vals, a, b)) # True # Generate random numbers: r = beta.rvs(a, b, size=1000) # And compare the histogram: ax.hist(r, normed=True, histtype='stepfilled', alpha=0.2) ax.legend(loc='best', frameon=False) plt.show()