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Cumulative Distribution Function
Chi-squared distribution cumulative distribution function.
Installation
npm install @stdlib/stats-base-dists-chisquare-cdf
Usage
var cdf = require( '@stdlib/stats-base-dists-chisquare-cdf' );
cdf( x, k )
Evaluates the cumulative distribution function (CDF) for a chi-squared distribution with degrees of freedom k
.
var y = cdf( 2.0, 1.0 );
y = cdf( 2.0, 3.0 );
y = cdf( 1.0, 0.5 );
y = cdf( -1.0, 2.0 );
y = cdf( -Infinity, 4.0 );
y = cdf( +Infinity, 4.0 );
If provided NaN
as any argument, the function returns NaN
.
var y = cdf( NaN, 1.0 );
y = cdf( 0.0, NaN );
If provided k < 0
, the function returns NaN
.
var y = cdf( 2.0, -2.0 );
If provided k = 0
, the function evaluates the CDF of a degenerate distribution centered at 0
.
var y = cdf( 2.0, 0.0 );
y = cdf( -2.0, 0.0 );
y = cdf( 0.0, 0.0 );
cdf.factory( k )
Returns a function for evaluating the cumulative distribution function for a chi-squared distribution with degrees of freedom k
.
var mycdf = cdf.factory( 3.0 );
var y = mycdf( 6.0 );
y = mycdf( 1.5 );
Examples
var randu = require( '@stdlib/random-base-randu' );
var round = require( '@stdlib/math-base-special-round' );
var cdf = require( '@stdlib/stats-base-dists-chisquare-cdf' );
var k;
var x;
var y;
var i;
for ( i = 0; i < 20; i++ ) {
x = randu() * 10.0;
k = round( randu()*5.0 );
y = cdf( x, k );
console.log( 'x: %d, k: %d, F(x;k): %d', x.toFixed( 4 ), k.toFixed( 4 ), y.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.
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License
See LICENSE.
Copyright
Copyright © 2016-2024. The Stdlib Authors.