@stdlib/stats-base-dists-triangular-stdev
v0.2.2
Published
Triangular distribution standard deviation.
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Standard Deviation
Triangular distribution standard deviation.
The standard deviation for a triangular random variable is
where a
is the lower limit, b
is the upper limit, and c
is the mode.
Installation
npm install @stdlib/stats-base-dists-triangular-stdev
Usage
var stdev = require( '@stdlib/stats-base-dists-triangular-stdev' );
stdev( a, b, c )
Returns the standard deviation of a triangular distribution with minimum support a
, maximum supportb
, and mode c
.
var v = stdev( 0.0, 1.0, 0.8 );
// returns ~0.216
v = stdev( 4.0, 12.0, 5.0 );
// returns ~1.78
v = stdev( 2.0, 8.0, 5.0 );
// returns ~1.225
If provided NaN
as any argument, the function returns NaN
.
var v = stdev( NaN, 4.0, 2.0 );
// returns NaN
v = stdev( 0.0, NaN, 2.0 );
// returns NaN
v = stdev( 0.0, 4.0, NaN );
// returns NaN
If provided parameters not satisfying a <= c <= b
, the function returns NaN
.
var y = stdev( 1.0, 0.0, 1.5 );
// returns NaN
y = stdev( 0.0, 1.0, -1.0 );
// returns NaN
y = stdev( 0.0, -1.0, 0.5 );
// returns NaN
Examples
var randu = require( '@stdlib/random-base-randu' );
var stdev = require( '@stdlib/stats-base-dists-triangular-stdev' );
var a;
var b;
var c;
var v;
var i;
for ( i = 0; i < 10; i++ ) {
a = ( randu()*10.0 );
b = ( randu()*10.0 ) + a;
c = ( randu()*( b-a ) ) + a;
v = stdev( a, b, c );
console.log( 'a: %d, b: %d, c: %d, SD(X;a,b,c): %d', a.toFixed( 4 ), b.toFixed( 4 ), c.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.
Community
License
See LICENSE.
Copyright
Copyright © 2016-2024. The Stdlib Authors.