@stdlib/stats-base-dists-binomial-variance
v0.3.1TypeScript
Binomial distribution variance.
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Published by The Stdlib Authors
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About stdlib...
Variance
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> [Binomial][binomial-distribution] distribution [variance][variance].
The [variance][variance] for a [binomial][binomial-distribution] random variable is
where n is the number of trials and p is the success probability.
Installation
``bash`
npm install @stdlib/stats-base-dists-binomial-variance
Usage
`javascript`
var variance = require( '@stdlib/stats-base-dists-binomial-variance' );
#### variance( n, p )
Returns the [variance][variance] of a [binomial][binomial-distribution] distribution with number of trials n and success probability p.
`javascript
var v = variance( 20, 0.1 );
// returns 1.8
v = variance( 50, 0.5 );
// returns 12.5
`
If provided NaN as any argument, the function returns NaN.
`javascript
var v = variance( NaN, 0.5 );
// returns NaN
v = variance( 20, NaN );
// returns NaN
`
If provided a number of trials n which is not a nonnegative integer, the function returns NaN.
`javascript
var v = variance( 1.5, 0.5 );
// returns NaN
v = variance( -2.0, 0.5 );
// returns NaN
`
If provided a success probability p outside of [0,1], the function returns NaN.
`javascript
var v = variance( 20, -1.0 );
// returns NaN
v = variance( 20, 1.5 );
// returns NaN
`
Examples
`javascript
var discreteUniform = require( '@stdlib/random-array-discrete-uniform' );
var uniform = require( '@stdlib/random-array-uniform' );
var logEachMap = require( '@stdlib/console-log-each-map' );
var variance = require( '@stdlib/stats-base-dists-binomial-variance' );
var opts = {
'dtype': 'float64'
};
var n = discreteUniform( 10, 0, 100, opts );
var p = uniform( 10, 0.0, 1.0, opts );
logEachMap( 'n: %0.4f, p: %0.4f, Var(X;n,p): %0.4f', n, p, variance );
`
*
C APIs
$3
`c`
#include "stdlib/stats/base/dists/binomial/variance.h"
#### stdlib_base_dists_binomial_variance( n, p )
Returns the [variance][variance] of a [binomial][binomial-distribution] distribution with number of trials n and success probability p.
`c`
double out = stdlib_base_dists_binomial_variance( 100, 0.1 );
// returns 9.0
The function accepts the following arguments:
- n: [in] int32_t number of trials.[in] double
- p: success probability.
`c`
double stdlib_base_dists_binomial_variance( const int32_t n, const double p );
$3
`c
#include "stdlib/stats/base/dists/binomial/variance.h"
#include "stdlib/math/base/special/ceil.h"
#include
#include
#include
static double random_uniform( const double min, const double max ) {
double v = (double)rand() / ( (double)RAND_MAX + 1.0 );
return min + ( v * (max - min) );
}
int main( void ) {
int32_t n;
double p;
double y;
int i;
for ( i = 0; i < 25; i++ ) {
n = stdlib_base_ceil( random_uniform( 0.0, 100.0 ) );
p = random_uniform( 0.0, 1.0 );
y = stdlib_base_dists_binomial_variance( n, p );
printf( "n: %d, p: %lf, Var(X;n,p): %lf\n", n, p, y );
}
return 0;
}
`
*
Notice
This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].
#### Community
[![Chat][chat-image]][chat-url]
---
License
See [LICENSE][stdlib-license].
Copyright
Copyright © 2016-2026. The Stdlib [Authors][stdlib-authors].
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[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules
[deno-url]: https://github.com/stdlib-js/stats-base-dists-binomial-variance/tree/deno
[deno-readme]: https://github.com/stdlib-js/stats-base-dists-binomial-variance/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/stats-base-dists-binomial-variance/tree/umd
[umd-readme]: https://github.com/stdlib-js/stats-base-dists-binomial-variance/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/stats-base-dists-binomial-variance/tree/esm
[esm-readme]: https://github.com/stdlib-js/stats-base-dists-binomial-variance/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/stats-base-dists-binomial-variance/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/stats-base-dists-binomial-variance/main/LICENSE
[binomial-distribution]: https://en.wikipedia.org/wiki/Binomial_distribution
[variance]: https://en.wikipedia.org/wiki/Variance