Mean

Geometric distribution expected value.

The expected value for a geometric random variable is

double-struck upper E left-bracket upper X right-bracket equals StartFraction 1 minus p Over p EndFraction

where p is the success probability.

Usage

var mean = require( '@stdlib/math/base/dists/geometric/mean' );

mean( p )

Returns the expected value of a geometric distribution with success probability p.

var v = mean( 0.1 );
// returns 9.0

v = mean( 0.5 );
// returns 1.0

If provided a success probability p outside of [0,1], the function returns NaN.

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

v = mean( 1.5 );
// returns NaN

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

Examples

var randu = require( '@stdlib/random/base/randu' );
var round = require( '@stdlib/math/base/special/round' );
var mean = require( '@stdlib/math/base/dists/geometric/mean' );

var v;
var i;
var p;

for ( i = 0; i < 10; i++ ) {
    p = randu();
    v = mean( p );
    console.log( 'p: %d, E(X;p): %d', p.toFixed( 4 ), v.toFixed( 4 ) );
}