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Bernoulli Distribution
The Bernoulli distribution is a discrete probability density function, specifically giving outcomes 0 or 1.
Description
The distribution gives outcome 1 with probability p, and 0 with probability q = 1 - p. It is appropriate for modeling any binary event.
A variable distributed this way is notated like X ~ Bernoulli(p). (Sometimes shortened to 'Bern'.)
The sum of repeated and independent Bernoulli-distributed events are described by the binomial distribution.
Moments
The expected value is given as E[X] = p.
Variance is given as Var[X] = p(1 - p) = pq.
Usage
Sampling
If all frame listings have an equal probability of selection, sampling can be implemented like:
scalar p = .2 /* Probability of selection */ set seed 123456789 generate double r = runiform() generate sampled = (r < p)
The expected number of cases sampled is np; the sample size is described by the binomial distribution.