Variance

Planck distribution variance.

The variance for a Planck random variable is

where λ is the shape parameter.

Usage

var variance = require( '@stdlib/stats/base/dists/planck/variance' );

variance( lambda )

Returns the variance of a Planck distribution with shape parameter λ.

var v = variance( 0.1 );
// returns ~99.9167

v = variance( 1.5 );
// returns ~0.3697

If provided a shape parameter λ which is nonpositive, the function returns NaN.

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

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

Examples

var uniform = require( '@stdlib/random/array/uniform' );
var variance = require( '@stdlib/stats/base/dists/planck/variance' );

var lambda = uniform( 10, 0.1, 10.0 );

var v;
var i;
for ( i = 0; i < lambda.length; i++ ) {
    v = variance( lambda[ i ] );
    console.log( 'λ: %d, Var(X;λ): %d', lambda[ i ].toFixed( 4 ), v.toFixed( 4 ) );
}