numpy.random.mtrand.RandomState.geometric

RandomState.geometric(p, size=None)

Draw samples from the geometric distribution.

Bernoulli trials are experiments with one of two outcomes: success or failure (an example of such an experiment is flipping a coin). The geometric distribution models the number of trials that must be run in order to achieve success. It is therefore supported on the positive integers, k = 1, 2, ....

The probability mass function of the geometric distribution is

System Message: WARNING/2 (f(k) = (1 - p)^{k - 1} p )

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where p is the probability of success of an individual trial.

Parameters :

p : float

The probability of success of an individual trial.

size : tuple of ints

Number of values to draw from the distribution. The output is shaped according to size.

Returns :

out : ndarray

Samples from the geometric distribution, shaped according to size.

Examples

Draw ten thousand values from the geometric distribution, with the probability of an individual success equal to 0.35:

>>> z = np.random.geometric(p=0.35, size=10000)

How many trials succeeded after a single run?

>>> (z == 1).sum() / 10000.
0.34889999999999999 #random