Mid-range

Computes the mid-range (mid-extreme) of a numeric array.

The mid-range, or mid-extreme, is the arithmetic mean of the maximum and minimum values in a data set. It is the midpoint of the range and a measure of central tendency.

Installation

$ npm install compute-midrange

For use in the browser, use browserify.

Usage

To use the module,

var midrange = require( 'compute-midrange' );

midrange( arr[, sorted] )

Computes the mid-range of a numeric array.

var unsorted = [ 8, 2, 3, 9, 5, 1, 4, 100, 7, 0, 6 ];

var midr = midrange( unsorted );
// returns 50

If the input array is already sorted in ascending order, set the optional second argument to true.

var sorted = [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 100 ];

var midr = midrange( sorted, true );
// returns 50

Notes

If the input array is empty, returns NaN.

Examples

var data = new Array( 100 );

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

console.log( midrange( 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

License

MIT license.

Copyright

Copyright © 2014. Rebekah Smith.