@stdlib/stats/base/dists/laplace/mean/README.md

Standard library statistical functions.

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# Mean

> [Laplace][laplace-distribution] distribution [expected value][mean].

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The [expected value][mean] for a [Laplace][laplace-distribution] random variable with location `μ` and scale `b > 0` is

<!-- <equation class="equation" label="eq:laplace_expectation" align="center" raw="\mathbb{E}\left[ X \right] = \mu" alt="Expected value for a Laplace distribution."> -->

<div class="equation" align="center" data-raw-text="\mathbb{E}\left[ X \right] = \mu" data-equation="eq:laplace_expectation">
    <img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@51534079fef45e990850102147e8945fb023d1d0/lib/node_modules/@stdlib/stats/base/dists/laplace/mean/docs/img/equation_laplace_expectation.svg" alt="Expected value for a Laplace distribution.">
    <br>
</div>

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## Usage

```javascript
var mean = require( '@stdlib/stats/base/dists/laplace/mean' );
```

#### mean( mu, b )

Returns the [expected value][mean] for a [Laplace][laplace-distribution] distribution with location parameter `mu` and scale parameter `b`.

```javascript
var y = mean( 2.0, 1.0 );
// returns 2.0

y = mean( 0.0, 1.0 );
// returns 0.0

y = mean( -1.0, 4.0 );
// returns -1.0
```

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

```javascript
var y = mean( NaN, 1.0 );
// returns NaN

y = mean( 0.0, NaN );
// returns NaN
```

If provided `b <= 0`, the function returns `NaN`.

```javascript
var y = mean( 0.0, 0.0 );
// returns NaN

y = mean( 0.0, -1.0 );
// returns NaN
```

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## Examples

<!-- eslint no-undef: "error" -->

```javascript
var randu = require( '@stdlib/random/base/randu' );
var mean = require( '@stdlib/stats/base/dists/laplace/mean' );

var mu;
var b;
var y;
var i;

for ( i = 0; i < 10; i++ ) {
    mu = ( randu()*10.0 ) - 5.0;
    b = randu() * 20.0;
    y = mean( mu, b );
    console.log( 'µ: %d, b: %d, E(X;µ,b): %d', mu.toFixed( 4 ), b.toFixed( 4 ), y.toFixed( 4 ) );
}
```

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[laplace-distribution]: https://en.wikipedia.org/wiki/Laplace_distribution

[mean]: https://en.wikipedia.org/wiki/Mean

</section>

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