 # compute-trimean

Computes the trimean of a numeric array.

## Stats

StarsIssuesVersionUpdatedCreatedSize
compute-trimean
401.0.08 years ago8 years ago Trimean
!NPM versionnpm-imagenpm-url !Build Statustravis-imagetravis-url !Coverage Statuscoveralls-imagecoveralls-url !Dependenciesdependencies-imagedependencies-url
Computes the trimean of a numeric array.

The trimean (or Tukey's trimean) is defined as the weighted average of a distribution's median and its two quartiles. The statistic measures a probability distribution's location and is a statistically resistant L-estimator, having a breakdown point of 25%. The statistic combines the robustness of the median, while accounting for a distribution's shape.

## Installation

``\$ npm install compute-trimean``

For use in the browser, use browserify.

## Usage

To use the module,
``var trimean = require( 'compute-trimean' );``

#### trimean( arr, opts )

Computes the trimean of a numeric `array`.
``````var unsorted = [ 5, 8, 9, 1, 7, 6, 2 ];

var tri = trimean( unsorted );
// returns 5.5``````

If the input `array` is already `sorted` in ascending order, set the `sorted` options flag to `true`.
``````var sorted = [ 1, 2, 5, 6, 7, 8, 9 ];

var tri = trimean( sorted, {'sorted': true} );
// returns 5.5``````

Additional options are the same as for the quantile module and only apply when computing the first and third quartiles.

## Examples

``````var data = new Array( 100 );

for ( var i = 0; i < data.length; i++ ) {
data[ i ] = Math.round( Math.random()*100 );
}

console.log( trimean( data ) );``````

To run the example code from the top-level application directory,
``\$ node ./examples/index.js``

## Tests

### Unit

Unit tests use the Mocha test framework with Chai assertions. To run the tests, execute the following command in the top-level application directory:
``\$ make test``

All new feature development should have corresponding unit tests to validate correct functionality.

### Test Coverage

This repository uses Istanbul as its code coverage tool. To generate a test coverage report, execute the following command in the top-level application directory:
``\$ make test-cov``

Istanbul creates a `./reports/coverage` directory. To access an HTML version of the report,
``\$ make view-cov``