Mean
Kumaraswamy's double bounded distribution expected value.
The mean for a Kumaraswamy's double bounded random variable is
where a
is the first shape parameter, b
the second shape parameter, and Γ
denotes the gamma function.
Usage
var mean = require( '@stdlib/stats/base/dists/kumaraswamy/mean' );
mean( a, b )
Returns the expected value of a Kumaraswamy's double bounded distribution with first shape parameter a
and second shape parameter b
.
var v = mean( 1.5, 1.5 );
// returns ~0.512
v = mean( 4.0, 12.0 );
// returns ~0.481
v = mean( 2.0, 8.0 );
// returns ~0.3
If provided NaN
as any argument, the function returns NaN
.
var v = mean( NaN, 2.0 );
// returns NaN
v = mean( 2.0, NaN );
// returns NaN
If provided a <= 0
, the function returns NaN
.
var y = mean( -1.0, 2.0 );
// returns NaN
y = mean( 0.0, 2.0 );
// returns NaN
If provided b <= 0
, the function returns NaN
.
var y = mean( 2.0, -1.0 );
// returns NaN
y = mean( 2.0, 0.0 );
// returns NaN
Examples
var randu = require( '@stdlib/random/base/randu' );
var mean = require( '@stdlib/stats/base/dists/kumaraswamy/mean' );
var a;
var b;
var v;
var i;
for ( i = 0; i < 10; i++ ) {
a = randu() * 10.0;
b = randu() * 10.0;
v = mean( a, b );
console.log( 'a: %d, b: %d, E(X;a,b): %d', a.toFixed( 4 ), b.toFixed( 4 ), v.toFixed( 4 ) );
}