Functions and CALL Routines

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
Arguments
Details
Comparisons
See Also

Syntax

RANBIN(seed,n,p)

Arguments

seed

is a numeric constant, variable, or expression with an integer value. If seed [le] 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 [le] 50, np [le] 5, or n(1-p) [le] 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.