# compute-midmean

Computes the interquartile mean (midmean) of a numeric array.

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compute-midmean
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Midmean
!NPM versionnpm-imagenpm-url !Build Statustravis-imagetravis-url !Coverage Statuscoveralls-imagecoveralls-url !Dependenciesdependencies-imagedependencies-url
Computes the interquartile mean (midmean) of a numeric array.

## Installation

``\$ npm install compute-midmean``

For use in the browser, use browserify.

## Usage

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

#### midmean( arr, sorted )

Computes the midmean of a numeric `array`.
``````var unsorted = [ 5, 6, 7, 2, 1, 8, 4, 3 ];

var mean = midmean( unsorted );
// returns 4.5``````

If the input `array` is already `sorted` in ascending order, set the optional second argument to `true`.
``````var sorted = [ 1, 2, 3, 4, 5, 6, 7, 8 ];

var mean = midmean( sorted, true );
// returns 4.5``````

## Examples

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

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

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

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

## Notes

If provided an unsorted input `array`, the function is `O( N log(N) + m )`, where `N` is the input `array` length and `m` is the number of values located between the first and third quartiles. If the input `array` is already sorted in ascending order, the function is `O(m)`.
The midmean includes the values located between but not including the first and third quartiles. In the following examples, the values included in the midmean are in bold.
• 1,2,3,4,5,6,7,8 -> midmean: 4.5
``[1,2,__3,4,5__,6,7] -> midmean: 4``

## 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``