I found what I needed here Using the standard deviation and the 68–95–99 rule I had my dynamic thresholds. 
sub stdev{
        my($data) = @_;
        if(@$data == 1){
                return 0;
        }
        my $average = &average($data);
        my $sqtotal = 0;
        foreach(@$data) {
                $sqtotal += ($average-$_) ** 2;
        }
        my $std = ($sqtotal / (@$data-1)) ** 0.5;
        return $std;
}

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In reply to Re: Dynamic thresholds in report by mhearse
in thread Dynamic thresholds in report by mhearse

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