RANBIN Function

Returns a random variate from a binomial distribution.

Category:	Random Number
Tip:	If you want to change the seed value during execution, you must use the CALL RANBIN routine instead of the RANBIN function.

Syntax

RANBIN(seed,n,p)

Required Arguments

seed

is a numeric constant, variable, or expression with an integer value. If seed ≤ 0, the time of day is used to initialize the seed stream.

Range	seed < 2³¹−1
See	Seed Values for more information about seed values

n

is a numeric constant, variable, or expression with an integer value that specifies the number of independent Bernoulli trials parameter.

Range

n> 0

p

is a numeric constant, variable, or expression that specifies the probability of success.

Range

0 < p < 1

Details

The RANBIN function returns a variate that is generated from a binomial distribution with mean np and variance np(1−p). If n ≤ 50, np ≤ 5, or n(1–p) ≤ 5, an inverse transform method applied to a RANUNI uniform variate is used. If n > 50, np > 5, and n(1–p) > 5, the normal approximation to the binomial distribution is used. In that case, the Box-Muller transformation of RANUNI uniform variates is used.

For a discussion about seeds and streams of data, as well as examples of using the random-number functions, see Generating Multiple Variables from One Seed in Random-Number Functions .

Comparisons

The CALL RANBIN routine, an alternative to the RANBIN function, gives greater control of the seed and random number streams.