note 93199 deleted from function.stats-standard-deviation by danbrown
| From: | danbrown@php.net | Date: | Fri, 28 Aug 2009 00:14:25 +0000 |
| Subject: | note 93199 deleted from function.stats-standard-deviation by danbrown | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-159962@lists.php.net to get a copy of this message | ||
Note Submitter: Mike Feldman
----
The above deviation formula is incorrect. Here's a fixed version.
function deviation ($array){
$avg = average($array);
$variance=0;
foreach ($array as $value) {
$variance+=pow($value-$avg, 2);
}
$deviation = sqrt($variance/(count($array)-1));
return $deviation;
}