@stdlib/stats-base-dists-discrete-uniform-stdev NP

Standard Deviation

Discrete uniform distribution standard deviation.

The standard deviation for a discrete uniform random variable is

where a is the minimum support and b the maximum support of the distribution.

Installation

npm install @stdlib/stats-base-dists-discrete-uniform-stdev

Usage

var stdev = require( '@stdlib/stats-base-dists-discrete-uniform-stdev' );

stdev( a, b )

Returns the standard deviation of a discrete uniform distribution with parameters a (minimum support) and b (maximum support).

var v = stdev( 0, 1 );
// returns ~0.5

v = stdev( 4, 12 );
// returns ~2.582

v = stdev( -4, 4 );
// returns ~2.582

If a or b is not an integer value, the function returns NaN.

var v = stdev( 0.1, 2 );
// returns NaN

v = stdev( 0, 2.2 );
// returns NaN

v = stdev( NaN, 2 );
// returns NaN

v = stdev( 2, NaN );
// returns NaN

If provided a > b, the function returns NaN.

var v = stdev( 3, 2 );
// returns NaN

v = stdev( -1, -2 );
// returns NaN

Examples

var randint = require( '@stdlib/random-base-discrete-uniform' );
var stdev = require( '@stdlib/stats-base-dists-discrete-uniform-stdev' );

var randa = randint.factory( 0, 10 );
var randb = randint.factory();
var a;
var b;
var v;
var i;

for ( i = 0; i < 10; i++ ) {
    a = randa();
    b = randb( a, a+randa() );
    v = stdev( a, b );
    console.log( 'a: %d, b: %d, SD(X;a,b): %d', a.toFixed( 4 ), b.toFixed( 4 ), v.toFixed( 4 ) );
}

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.