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Hey everyone,
I just installed WP-Syntax for the WordPress and I want to test it out by posting javascript code for finding Standard Deviation, Variance, Average among numbers.
Without WP-Syntax
var str = 'This is a string.';
console.log( str ); //Boring!
With WP-Syntax
var str = 'hello world. Here I am!'; console.log( str ); //Nice colors!! |
Without more delay, here are the Statistics functions.
Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 | // Programmer: Larry Battle // Date: Mar 06, 2011 // Purpose: Calculate standard deviation, variance, and average among an array of numbers. var isArray = function (obj) { return Object.prototype.toString.call(obj) === "[object Array]"; }, getNumWithSetDec = function( num, numOfDec ){ var pow10s = Math.pow( 10, numOfDec || 0 ); return ( numOfDec ) ? Math.round( pow10s * num ) / pow10s : num; }, getAverageFromNumArr = function( numArr, numOfDec ){ if( !isArray( numArr ) ){ return false; } var i = numArr.length, sum = 0; while( i-- ){ sum += numArr[ i ]; } return getNumWithSetDec( (sum / numArr.length ), numOfDec ); }, getVariance = function( numArr, numOfDec ){ if( !isArray(numArr) ){ return false; } var avg = getAverageFromNumArr( numArr, numOfDec ), i = numArr.length, v = 0; while( i-- ){ v += Math.pow( (numArr[ i ] - avg), 2 ); } v /= numArr.length; return getNumWithSetDec( v, numOfDec ); }, getStandardDeviation = function( numArr, numOfDec ){ if( !isArray(numArr) ){ return false; } var stdDev = Math.sqrt( getVariance( numArr, numOfDec ) ); return getNumWithSetDec( stdDev, numOfDec ); }; |
Usage
Testing with numbers from wiki
1 2 3 4 5 6 | var arrOfNums = [ 2,4,4,4,5,5,7,9 ], precision = 4; getAverageFromNumArr( arrOfNums, precision ); //returns 5 getVariance( arrOfNums, precision ); // returns 4 getStandardDeviation( arrOfNums, precision ); //returns 2 |
Enjoy! 🙂
Update
For those wanting more statistical functions, use jStat : a JavaScript statistical library. by John Resig.
jStat is a statistical library written in JavaScript that allows you to perform advanced statistical operations without the need of a dedicated statistical language (i.e. MATLAB or R).
Update 2
Please read this for more information “http://easycalculation.com/statistics/learn-standard-deviation.php”
