@stdlib/stats-base-dists-poisson-stdev
v0.2.2
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Poisson distribution standard deviation.
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Standard Deviation
Poisson distribution standard deviation.
The standard deviation for a Poisson random variable is
where λ
is the mean parameter.
Installation
npm install @stdlib/stats-base-dists-poisson-stdev
Usage
var stdev = require( '@stdlib/stats-base-dists-poisson-stdev' );
stdev( lambda )
Returns the standard deviation of a Poisson distribution with mean parameter lambda
.
var v = stdev( 9.0 );
// returns 3.0
v = stdev( 0.5 );
// returns ~0.707
If provided lambda < 0
, the function returns NaN
.
var v = stdev( -1.0 );
// returns NaN
Examples
var randu = require( '@stdlib/random-base-randu' );
var round = require( '@stdlib/math-base-special-round' );
var stdev = require( '@stdlib/stats-base-dists-poisson-stdev' );
var lambda;
var v;
var i;
for ( i = 0; i < 10; i++ ) {
lambda = randu() * 20.0;
v = stdev( lambda );
console.log( 'λ: %d, SD(X;λ): %d', lambda.toFixed( 4 ), v.toFixed( 4 ) );
}
Notice
This package is part of 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, see the main project repository.
Community
License
See LICENSE.
Copyright
Copyright © 2016-2024. The Stdlib Authors.