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    require_once 'variance.php';
    require_once 'mean.php';

    function kurtosis($valArray, $isSample, $isExcess){
     $mean = mean($valArray);
        $variance = 0;
        $mult = 0;
        $moment4 = 0;
        $length = 0;

        foreach($valArray as $k => $moment4):
            $mult -= $mean;
            $mult *= $mult;
            $mult *= $mult;
            $moment4 += $mult;
        $variance = variance($valArray, $mean, $isSample);
        $moment2 = ($variance *= $variance);
        $kurt = $length *($moment4 / $moment2);
        //normal kurtosis
        if((!$isSample) && (!$isExcess)):
            $kurtosis = $kurt;
            //excess kurtosis
        elseif(($isExcess) && (!$isSample)):
            $kurtosis = ($kurt - 3);
            // sample kurtosis
        elseif((!$isExcess) && ($isSample)):
            $n3 = ($length * $length * $length);
            $n2 = ($length * $length);
            $kurt = $n2 / $n3;
            $kurtosis = $kurt *($moment4 / $moment2);
            //sample excess kurtosis
            $n3 = ($length * $length * $length);
            $n2 = ($length * $length);
            $kurt = ( ($n2 / $n3) * ($moment4 / $moment2) );
            $kurtosis = $kurt - 3;
        return $kurtosis;
NeverJustHere 19-Apr-14 17:23pm    
Inf possibly means you are performing a divide by zero somewhere in the calculation.

Since we don't have the data you are using, we cannot determine exactly where the error is.

I suggest you put some debugging code in to see what all the divisions are actually doing. Hopefully then, the issue will become clear to you.
Member 10287010 22-Apr-14 20:49pm    
thanks for the insight, i actually found out my error during the weekend. i was supposed to used moent4 where i had placed mult, and mult's value was 0.. but teaching me how to creat an array from database values would help with my current peril

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