Chi-squared distribution expected value.
The expected value for a chi-squared random variable is
where k
is the degrees of freedom.
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var mean = require( '@stdlib/stats-base-dists-chisquare-mean' );
Returns the expected value of a chi-squared distribution with degrees of freedom k
.
var v = mean( 9.0 );
// returns 9.0
v = mean( 0.5 );
// returns 0.5
If provided k < 0
, the function returns NaN
.
var v = mean( -1.0 );
// returns NaN
var randu = require( '@stdlib/random-base-randu' );
var round = require( '@stdlib/math-base-special-round' );
var mean = require( '@stdlib/stats-base-dists-chisquare-mean' );
var k;
var v;
var i;
for ( i = 0; i < 10; i++ ) {
k = randu() * 20.0;
v = mean( k );
console.log( 'k: %d, E(X,k): %d', k.toFixed( 4 ), v.toFixed( 4 ) );
}
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