| NamePros Regular Name: Lee Location: United Kingdom Join Date: Mar 2006 | [PHP] PMCC Calculator
Possibly one of the most useless functions, but i thought i'd post it anyway, as it may be of use to someone. It calculates PMCC between to set's of data, i created it because excel was continously throwing up errors with all the data I entered.
pmcc.class.php PHP Code: <?php
/*
PMCC (Product Moment Correlation Coefficient) Class
Takes 2 sets of data, and calculates their relationship using the PMCC formula
and returns a value between -1 and 1
Created by: Lee Findlow
Contact: leefindlow@gmail.com
Website: http://conceptsublime.com
*/
class PMCC{
//Variables Used, for range x and range y
var $DataX;
var $DataY;
//Function to create Sxx
function Sxx(){
//Disable Error Reporting
error_reporting(0);
$NumOfAll = count($this->DataX);
$SumOfAll = array_sum($this->DataX);
$MeanOfAll = $SumOfAll/$NumOfAll;
//Calculate Σ(Xi-[Mean Of All X's])^2
$RunningTotal = 0;
foreach($this->DataX as $Sxx){
$RunningTotal += pow(($Sxx-$MeanOfAll),2);
}
return $RunningTotal;
}
//Function to create Syy
function Syy(){
//Disable Error Reporting
error_reporting(0);
$NumOfAll = count($this->DataY);
$SumOfAll = array_sum($this->DataY);
$MeanOfAll = $SumOfAll/$NumOfAll;
//Calculate Σ(Yi-[Mean Of All Y's])^2
$RunningTotal = 0;
foreach($this->DataY as $Syy){
$RunningTotal += pow(($Syy-$MeanOfAll),2);
}
return $RunningTotal;
}
//Function to create Sxy
function Sxy(){
//Disable Error Reporting
error_reporting(0);
$NumOfAll_X = count($this->DataX);
$SumOfAll_X = array_sum($this->DataX);
$MeanOfAll_X = $SumOfAll_X/$NumOfAll_X;
$NumOfAll_Y = count($this->DataX);
$SumOfAll_Y = array_sum($this->DataX);
$MeanOfAll_Y = $SumOfAll_Y/$NumOfAll_Y;
$NumOfAll = min($NumOfAll_X,$NumOfAll_Y);
//Loop Through and create Σ(Xi-[Mean Of All X's])(Yi-[Mean Of All Y's])
$i = 0;
$RunningTotal = 0;
while($i < $NumOfAll){
$X = $this->DataX[$i] - $MeanOfAll_X;
$Y = ($this->DataY[$i]-$MeanOfAll_Y);
$RunningTotal+= $X * $Y;
$i++;
}
return $RunningTotal;
}
//Combine All Functions to Create PMCC Value
function PMCC(){
//Disable Error Reporting
error_reporting(0);
//Calculate Lower Part
$SxxSyy = $this->Sxx()*$this->Syy();
$SxxSyy = sqrt($SxxSyy);
//Do Calculation
$PMCC = $this->Sxy()/$SxxSyy;
//Return Answer
return $PMCC;
}
};
?>
The data you want to compare is entered as an array, as displayed above
More Information - http://en.wikipedia.org/wiki/PMCC
Lee 
Last edited by lee101 : 01-21-2007 at 09:49 AM.
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