Probability Density Function

Wilcoxon signed rank test statistic probability density function.

Usage

var pdf = require( '@stdlib/stats/base/dists/signrank/pdf' );

pdf( x, n )

Evaluates the probability density function of the Wilcoxon signed rank test statistic with n observations.

var y = pdf( 7.0, 9 );
// returns ~0.0098

y = pdf( 7.0, 6 );
// returns ~0.063

y = pdf( -1.0, 40 );
// returns 0.0

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

var y = pdf( NaN, 8 );
// returns NaN

y = pdf( 0.0, NaN );
// returns NaN

If provided x < 0, the function returns NaN.

var y = pdf( 2.0, -1.0 );
// returns NaN

If not provided a positive integer for n, the function returns NaN.

var y = pdf( 2.0, 0 );
// returns NaN

y = pdf( 2.0, -2 );
// returns NaN

y = pdf( 2.0, 8.9 );
// returns NaN

pdf.factory( n )

Returns a function for evaluating the probability density function of the Wilcoxon signed rank test statistic with n observations.

var mypdf = pdf.factory( 8 );
var y = mypdf( 4.0 );
// returns ~0.008

y = mypdf( 17.0 );
// returns ~0.051

Examples

var ceil = require( '@stdlib/math/base/special/ceil' );
var randu = require( '@stdlib/random/base/randu' );
var pdf = require( '@stdlib/stats/base/dists/signrank/pdf' );

var n;
var x;
var y;
var i;

for ( i = 0; i < 10; i++ ) {
    x = randu() * 30.0;
    n = ceil( randu() * 30.0 );
    y = pdf( x, n );
    console.log( 'x: %d, n: %d, F(x;n): %d', x.toFixed( 4 ), n.toFixed( 4 ), y.toFixed( 4 ) );
}