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

Mean

F distribution expected value.

The expected value for a F random variable with numerator degrees of freedom d1 > 0 and denominator degrees of freedom d2 > 0 is defined as

Installation

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

Usage

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

mean( d1, d2 )

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

var v = mean( 4.0, 5.0 );
// returns ~1.667

v = mean( 4.0, 12.0 );
// returns ~1.2

v = mean( 8.0, 4.0 );
// returns 2.0

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

var v = mean( NaN, 3.0 );
// returns NaN

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

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

var v = mean( 0.0, 3.0 );
// returns NaN

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

If provided d2 <= 2, the function returns NaN.

var v = mean( 2.0, 1.8 );
// returns NaN

v = mean( 1.0, -1.0 );
// returns NaN

Examples

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

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

for ( i = 0; i < 10; i++ ) {
    d1 = ( randu()*10.0 ) + EPS;
    d2 = ( randu()*10.0 ) + EPS;
    v = mean( d1, d2 );
    console.log( 'd1: %d, d2: %d, E(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.