z-Scores(standard deviation and mean) in PHP

Question

I am trying to calculate Z-scores using PHP. Essentially, I am looking for the most efficient way to calculate the mean and standard deviation of a data set (PHP array). Any

Answer 1

The topic is pretty old, but actually I guess you can get the substitute of STDEV.P function from Excel easily using the function like below.

function stdev_p($arr) {
    $arr2 = array();
    $mean = array_sum($arr)/count($arr);
    for ($x = 0; $x