Hướng dẫn poisson distribution python scipy
A Poisson discrete random variable. As an instance of the
Notes The probability mass function for \[f(k) = \exp(-\mu) \frac{\mu^k}{k!}\] for \(k \ge 0\).
The probability mass function above is defined in the “standardized” form. To shift distribution use the Examples >>> from scipy.stats import poisson >>> import matplotlib.pyplot as plt >>> fig, ax = plt.subplots(1, 1) Calculate the first four moments: >>> mu = 0.6 >>> mean, var, skew, kurt = poisson.stats(mu, moments='mvsk') Display the probability mass function (
>>> x = np.arange(poisson.ppf(0.01, mu), ... poisson.ppf(0.99, mu)) >>> ax.plot(x, poisson.pmf(x, mu), 'bo', ms=8, label='poisson pmf') >>> ax.vlines(x, 0, poisson.pmf(x, mu), colors='b', lw=5, alpha=0.5) Alternatively, the distribution object can be called (as a function) to fix the shape and location. This returns a “frozen” RV object holding the given parameters fixed. Freeze the distribution and display the frozen >>> rv = poisson(mu) >>> ax.vlines(x, 0, rv.pmf(x), colors='k', linestyles='-', lw=1, ... label='frozen pmf') >>> ax.legend(loc='best', frameon=False) >>> plt.show() Check accuracy of >>> prob = poisson.cdf(x, mu) >>> np.allclose(x, poisson.ppf(prob, mu)) True Generate random numbers: >>> r = poisson.rvs(mu, size=1000) Methods
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