Median

Kumaraswamy's double bounded distribution median.

The median for a Kumaraswamy's double bounded random variable is

upper M e d i a n left-parenthesis upper X right-parenthesis equals left-parenthesis 1 minus 2 Superscript negative 1 slash b Baseline right-parenthesis Superscript 1 slash a

where a is the first shape parameter and b the second shape parameter.

Usage

var median = require( '@stdlib/math/base/dists/kumaraswamy/median' );

median( a, b )

Returns the median of a Kumaraswamy's double bounded distribution with first shape parameter a and second shape parameter b.

var v = median( 1.0, 1.0 );
// returns 0.5

v = median( 4.0, 12.0 );
// returns ~0.487

v = median( 2.0, 8.0 );
// returns ~0.288

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

var v = median( NaN, 2.0 );
// returns NaN

v = median( 2.0, NaN );
// returns NaN

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

var y = median( -1.0, 0.5 );
// returns NaN

y = median( 0.0, 0.5 );
// returns NaN

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

var y = median( 0.5, -1.0 );
// returns NaN

y = median( 0.5, 0.0 );
// returns NaN

Examples

var randu = require( '@stdlib/random/base/randu' );
var median = require( '@stdlib/math/base/dists/kumaraswamy/median' );

var a;
var b;
var v;
var i;

for ( i = 0; i < 10; i++ ) {
    a = randu() * 10.0;
    b = randu() * 10.0;
    v = median( a, b );
    console.log( 'a: %d, b: %d, Median(X;a,b): %d', a.toFixed( 4 ), b.toFixed( 4 ), v.toFixed( 4 ) );
}