PHP Salt

	$aryNumbers = array(5,6,7,8,10,200);
        $stats = psStats($aryNumbers);
	print_r($stats);


Output:
Array
(
    [n] => 6
    [sum] => 236
    [avg] => 39.333333333333
    [dev] => 71.869480464396
    [ddis] => 83.333333333333
    [dlo] => -32.536147131063
    [dhi] => 111.20281379773
    [median] => 7.5
    [harmonic] => 8.1133290405666
    [mode] => 5
    [max] => 200
    [min] => 5
    [range] => 195

    [xout] => Array
        (
            [n] => 5
            [sum] => 36
            [avg] => 7.2
            [dev] => 1.7204650534085
            [ddis] => 60
            [dlo] => 5.4795349465915
            [dhi] => 8.9204650534085
            [median] => 7
            [mode] => 5
            [max] => 10
            [min] => 5
            [range] => 5
        )

    [sample] => 0
)




[n]        => number of data items 
[sum]      => sum of data items
[avg]      => average (mean)
[dev]      => standard deviation
[ddis]     => percent of data within std deviation
[dlo]      => standard deviation low from mean (avg - dev)
[dhi]      => standard deviation high limit from mean (avg + dev)
[median]   => median, middle value data
[harmonic] => harmonic mean
[mode]     => mode, the most apearing value in the data
[max]      => largest number
[min]      => smallest number
[range]    => value range (max-min)
[xout]     => stats run on data within the std dev range (remove outliers)

// $s = 1 when using a sample of a data set
// $o = internal use for re-entry, so we dont loop
function psStats($ary,$s=0,$o=1)
{
	$sSum = 0;
	$sVSum = 0;
	$sXSum = 0;

	$sN = count($ary);

	// get the average and a few other items
	foreach ($ary as $key=>$val)
	  {
	  $sSum += $val; 	// used for average
	  @$asMode[$val]++;	// finding the mode
	  @$asMed[] = $val;	// build a keyless set for finding median
	  }


	$sAvg = $sSum / $sN;	// calc average

	
	asort($asMode);		// sort the mode
	//print_r($asMode);
	end($asMode);
	$sMode = key($asMode);


	asort($asMed);		// sort the median data
	$sMid = floor( $sN / 2 );  // get the median index
	if ( $sMid == ($sN/2) )
	  {
	  $sML = $asMed[$sMid-1];
	  $sMH = $asMed[$sMid];
	  $sMed = ($sML + $sMH) / 2;
	  //print "  ($sML:$sMH)  ";
	  }
	else
	  {
	  $sMed = $asMed[$sMid];
	  }


	// harmonic mean
	$hSum = 0;
	foreach ($ary as $key=>$val)
	  {
	  $hSum += (1 / $val);
	  }
	$sHarmonic = count($ary) / $hSum;



	// get the variance
	foreach ($ary as $key=>$val)
	  {
	  $dif = $val - $sAvg;
	  $sVSum += ($dif * $dif);
	  }

	// calc std deviation
	$sDev = sqrt($sVSum / ($sN - $s) );
	$sDevLow = $sAvg - $sDev;
	$sDevHigh = $sAvg + $sDev;




	// gather a data list exluding outliers past the std deviation
	foreach ($ary as $key=>$val)
	  {
	  if ( ($val >= $sDevLow) && ($val <= $sDevHigh) )
	    {
	    @$saGData[] = $val;
	    }
	  }


	$sND = count($saGData); // number of data points within std deviation

	// get stats for this group exluding outliers
	if ( $o == 1 ) // check if we re-enter for deeper stats
	  {
	  $asGrp = psStats($saGData,0,0);
	  unset($asGrp['xout']);
	  unset($asGrp['sample']);
	  }


	$res['n'] = $sN;
	$res['sum'] = $sSum;
	$res['avg'] = $sAvg;
	$res['dev'] = $sDev;
	$res['ddis'] = ($sND/$sN) * 100;
	$res['dlo'] = $sDevLow;
	$res['dhi'] = $sDevHigh;
	$res['harmonic'] = $sHarmonic;

	$res['median'] = $sMed;
	$res['mode'] = $sMode;

	$res['max'] = max($ary);
	$res['min'] = min($ary);
	$res['range'] = max($ary) - min($ary);

	if ($o == 1) { $res['xout'] = $asGrp; }


	$res['sample'] = $s;

	return $res;

}