Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Calculation/Statistical.php
public static function FISHER($value)
    {
        $value = Functions::flattenSingleValue($value);

        if (is_numeric($value)) {
            if (($value <= -1) || ($value >= 1)) {
                return Functions::NAN();
            }

            return 0.5 * log((1 + $value) / (1 - $value));
        }

        return Functions::VALUE();
    }
public static function FISHER($value)
    {
        $value = Functions::flattenSingleValue($value);

        if (is_numeric($value)) {
            if (($value <= -1) || ($value >= 1)) {
                return Functions::NAN();
            }

            return 0.5 * log((1 + $value) / (1 - $value));
        }

        return Functions::VALUE();
    }
FISHER.

Returns the Fisher transformation at x. This transformation produces a function that
is normally distributed rather than skewed. Use this function to perform hypothesis
testing on the correlation coefficient.

@param float $value

@return float