fix statistics function during documentation update

Math/Statistic/Average.php

@@ -172,6 +172,8 @@ final class Average
      *
      * Example: ([1, 2, 2, 3, 4, 4, 2])
      *
+     * @latex \mu = mean = \frac{1}{n}\sum_{i=1}^{n}a_i
+     *
      * @param array<int, int|float> $values Values
      * @param int                   $offset Offset for outlier
      *

Math/Statistic/Correlation.php

@@ -39,6 +39,8 @@ final class Correlation
      *
      * Example: ([4, 5, 9, 1, 3], [4, 5, 9, 1, 3])
      *
+     * @latex \rho_{XY} = \frac{cov(X, Y)}{\sigma_X \sigma_Y}
+     *
      * @param array<int|float> $x Values
      * @param array<int|float> $y Values
      *
@@ -56,6 +58,8 @@ final class Correlation
      *
      * Example: ([4, 5, 9, 1, 3], [4, 5, 9, 1, 3])
      *
+     * @latex \rho_{XY} = \frac{cov(X, Y)}{\sigma_X \sigma_Y}
+     *
      * @param array<int|float> $x Values
      * @param array<int|float> $y Values
      *

Math/Statistic/MeasureOfDispersion.php

@@ -212,7 +212,7 @@ final class MeasureOfDispersion
      *
      * Example: ([4, 5, 9, 1, 3], [4, 5, 9, 1, 3])
      *
-     * @latex \sigma_{XY} = cov(X, Y) = \sum_{i = 1}^{N}\frac{\left(x_{i} - \bar{X}\right) \left(y_{i} - \bar{Y}\right)}{N - 1}
+     * @latex cov(X,Y) = \frac{1}{N} \sum_{i = 1}^{N}\left(x_{i} - \bar{X}\right)\left(y_{i} - \bar{Y}\right)
      *
      * @param array<int, int|float> $x     Values
      * @param array<int, int|float> $y     Values
@@ -255,7 +255,7 @@ final class MeasureOfDispersion
      *
      * Example: ([4, 5, 9, 1, 3], [4, 5, 9, 1, 3])
      *
-     * @latex \sigma_{XY} = cov(X, Y) = \sum_{i = 1}^{N}\frac{\left(x_{i} - \bar{X}\right) \left(y_{i} - \bar{Y}\right)}{N - 1}
+     * @latex cov(X,Y) = \frac{1}{N - 1} \sum_{i = 1}^{N}\left(x_{i} - \bar{X}\right)\left(y_{i} - \bar{Y}\right)
      *
      * @param array<int, int|float> $x     Values
      * @param array<int, int|float> $y     Values

Math/Stochastic/Distribution/ChiSquaredDistribution.php

@@ -77,6 +77,8 @@ final class ChiSquaredDistribution
     /**
      * Test hypthesis.
      *
+     * Goodness of fit test.
+     *
      * @param array $dataset      Values
      * @param array $expected     Expected values based on probability
      * @param float $significance Significance

Utils/ArrayUtils.php

@@ -75,6 +75,20 @@ final class ArrayUtils
         return $data;
     }
 
+    /**
+     * Calculate the range of the array
+     *
+     * @param int[]|float[] $values Numeric values
+     *
+     * @return int|float Range of the array
+     *
+     * @since 1.0.0
+     */
+    public static function range(array $values) : int|float
+    {
+        return \max($values) - \min($values);
+    }
+
     /**
      * Set element in array by path
      *