Variance

Degenerate distribution variance.

The variance for a degenerate random variable is

where μ is the constant value of the distribution.

Usage

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

variance( mu )

Returns the variance of a degenerate distribution with constant value mu.

var v = variance( 10.0 );
// returns 0.0

v = variance( -0.5 );
// returns 0.0

v = variance( NaN );
// returns NaN

Examples

var randu = require( '@stdlib/random/base/randu' );
var variance = require( '@stdlib/stats/base/dists/degenerate/variance' );

var mu;
var v;
var i;

for ( i = 0; i < 10; i++ ) {
    mu = randu();
    v = variance( mu );
    console.log( 'µ: %d, Var(X;µ): %d', mu.toFixed( 4 ), v.toFixed( 4 ) );
}

C APIs

Usage

#include "stdlib/stats/base/dists/degenerate/variance.h"

stdlib_base_dists_degenerate_variance( mu )

Returns the variance of a degenerate distribution.

double out = stdlib_base_dists_degenerate_variance( 0.1 );
// returns 0.0

The function accepts the following arguments:

mu: [in] double constant value of distribution.

double stdlib_base_dists_degenerate_variance( const double mu );

Examples

#include "stdlib/stats/base/dists/degenerate/variance.h"
#include <stdlib.h>
#include <stdio.h>

static double random_uniform( const double min, const double max ) {
    double v = (double)rand() / ( (double)RAND_MAX + 1.0 );
    return min + ( v*(max-min) );
}

int main( void ) {
    double mu;
    double y;
    int i;

    for ( i = 0; i < 25; i++ ) {
        mu = random_uniform( -50.0, 50.0 );
        y = stdlib_base_dists_degenerate_variance( mu );
        printf( "µ: %lf, Var(X;µ): %lf\n", mu, y );
    }
}