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lib/PhpSpreadsheet/Calculation/Statistical/StandardDeviations.php

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+<?php
+
+namespace PhpOffice\PhpSpreadsheet\Calculation\Statistical;
+
+class StandardDeviations
+{
+    /**
+     * STDEV.
+     *
+     * Estimates standard deviation based on a sample. The standard deviation is a measure of how
+     *        widely values are dispersed from the average value (the mean).
+     *
+     * Excel Function:
+     *        STDEV(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     *
+     * @return float|string The result, or a string containing an error
+     */
+    public static function STDEV(mixed ...$args)
+    {
+        $result = Variances::VAR(...$args);
+        if (!is_numeric($result)) {
+            return $result;
+        }
+
+        return sqrt((float) $result);
+    }
+
+    /**
+     * STDEVA.
+     *
+     * Estimates standard deviation based on a sample, including numbers, text, and logical values
+     *
+     * Excel Function:
+     *        STDEVA(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     */
+    public static function STDEVA(mixed ...$args): float|string
+    {
+        $result = Variances::VARA(...$args);
+        if (!is_numeric($result)) {
+            return $result;
+        }
+
+        return sqrt((float) $result);
+    }
+
+    /**
+     * STDEVP.
+     *
+     * Calculates standard deviation based on the entire population
+     *
+     * Excel Function:
+     *        STDEVP(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     */
+    public static function STDEVP(mixed ...$args): float|string
+    {
+        $result = Variances::VARP(...$args);
+        if (!is_numeric($result)) {
+            return $result;
+        }
+
+        return sqrt((float) $result);
+    }
+
+    /**
+     * STDEVPA.
+     *
+     * Calculates standard deviation based on the entire population, including numbers, text, and logical values
+     *
+     * Excel Function:
+     *        STDEVPA(value1[,value2[, ...]])
+     *
+     * @param mixed ...$args Data values
+     */
+    public static function STDEVPA(mixed ...$args): float|string
+    {
+        $result = Variances::VARPA(...$args);
+        if (!is_numeric($result)) {
+            return $result;
+        }
+
+        return sqrt((float) $result);
+    }
+}