note 86300 added to book.math

This is the only function I searched that I did not find anywhere on the Internet. This function calculates standard normal cumulative distribution for a particular value. This is NORMSDIST(x) in MS-Excel or OpenOffice.org Calc program.

<?
function normalDist($zScore) {
	$p = floatval(0.2316419);
	$b1 = floatval(0.319381530);
	$b2 = floatval(-0.356563782);
	$b3 = floatval(1.781477937);
	$b4 = floatval(-1.821255978);
	$b5 = floatval(1.330274429);
	$t = 1/(1 + ($p * floatval($zScore)));
	$zx = (1/(sqrt(2 * pi())) * (exp(0 - pow($zScore, 2)/2)));

	$px = 1 - floatval($zx) * (($b1 * $t) + ($b2 * pow($t, 2)) + ($b3 * pow($t, 3)) + ($b4 * pow($t, 4)) + ($b5 * pow($t,5)));
	return $px;
}
?>
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Server IP: 209.41.74.194
Probable Submitter: 98.206.252.71
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