Probability Density Function

Wilcoxon signed rank test statistic probability density function.

Installation

npm install @stdlib/stats-base-dists-signrank-pdf

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 ) );
}

C APIs

Usage

#include "stdlib/stats/base/dists/signrank/pdf.h"

stdlib_base_dists_signrank_pdf( x, n )

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

double out = stdlib_base_dists_signrank_pdf( 7.0, 9 );
// returns ~0.01

The function accepts the following arguments:

• x: [in] double input value.
• n: [in] int32_t number of observations.

double stdlib_base_dists_signrank_pdf( const double x, const int32_t n );

Examples

#include "stdlib/stats/base/dists/signrank/pdf.h"
#include "stdlib/math/base/special/ceil.h"
#include <stdlib.h>
#include <stdio.h>
#include <stdint.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 ) {
    int32_t n;
    double x;
    double y;
    int i;

    for ( i = 0; i < 25; i++ ) {
        x = random_uniform( 0, 30.0 );
        n = (int32_t)stdlib_base_ceil( random_uniform( 1.0, 30.0 ) );
        y = stdlib_base_dists_signrank_pdf( x, n );
        printf( "x: %lf, n: %d, f(x;n): %lf\n", x, n, y );
    }
}

Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

Community

License

See LICENSE.

Copyright

Copyright © 2016-2026. The Stdlib Authors.