# @stdlib/stats-base-dists-t-variance

0.2.2 • Public • Published

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# Variance

Student's t distribution variance.

The variance for a Student's t random variable with degrees of freedom `ν` is

For `ν` smaller than one, the variance is not defined.

## Installation

`npm install @stdlib/stats-base-dists-t-variance`

## Usage

`var variance = require( '@stdlib/stats-base-dists-t-variance' );`

#### variance( v )

Returns the variance of a Student's t distribution with degrees of freedom `v`.

```var y = variance( 9.0 );
// returns ~1.286

y = variance( 3.5 );
// returns ~2.333```

If provided `1 < v <= 2`, the function returns `infinity`.

```var y = variance( 1.5 );
// returns Infinity

y = variance( 2.0 );
// returns Infinity```

If provided `v <= 1`, the function returns `NaN`.

```var y = variance( -1.0 );
// returns NaN

y = variance( 0.8 );
// returns NaN```

## Examples

```var randu = require( '@stdlib/random-base-randu' );
var round = require( '@stdlib/math-base-special-round' );
var variance = require( '@stdlib/stats-base-dists-t-variance' );

var v;
var y;
var i;

for ( i = 0; i < 10; i++ ) {
v = randu() * 20.0;
y = variance( v );
console.log( 'v: %d, Var(X,v): %d', v.toFixed( 4 ), y.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.

## Package Sidebar

### Install

`npm i @stdlib/stats-base-dists-t-variance`

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