@stdlib/stats-base-dists-f-stdev NPM

Standard Deviation

F distribution standard deviation.

The standard deviation for a F random variable is

for d1 > 0 and d2 > 4. Otherwise, the standard deviation is not defined.

Installation

npm install @stdlib/stats-base-dists-f-stdev

Usage

var stdev = require( '@stdlib/stats-base-dists-f-stdev' );

stdev( d1, d2 )

Returns the standard deviation of a F distribution with parameters d1 (numerator degrees of freedom) and d2 (denominator degrees of freedom).

var v = stdev( 4.0, 5.0 );
// returns ~3.118

v = stdev( 4.0, 12.0 );
// returns ~1.122

v = stdev( 8.0, 5.0 );
// returns ~2.764

If provided NaN as any argument, the function returns NaN.

var v = stdev( NaN, 5.0 );
// returns NaN

v = stdev( 3.0, NaN );
// returns NaN

If provided d1 <= 0, the function returns NaN.

var v = stdev( 0.0, 5.0 );
// returns NaN

v = stdev( -1.0, 5.0 );
// returns NaN

If provided d2 <= 4, the function returns NaN.

var v = stdev( 3.0, 4.0 );
// returns NaN

v = stdev( 3.0, -1.0 );
// returns NaN

Examples

var randu = require( '@stdlib/random-base-randu' );
var EPS = require( '@stdlib/constants-float64-eps' );
var stdev = require( '@stdlib/stats-base-dists-f-stdev' );

var d1;
var d2;
var v;
var i;

for ( i = 0; i < 10; i++ ) {
    d1 = ( randu()*10.0 ) + EPS;
    d2 = ( randu()*20.0 ) + EPS;
    v = stdev( d1, d2 );
    console.log( 'd1: %d, d2: %d, SD(X;d1,d2): %d', d1.toFixed( 4 ), d2.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.