PHP - Stats Stat Correlation() Function

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Definition and Usage

The stats_stat_correlation() function can return the Pearson correlation coefficient of two data sets.

Syntax

  float stats_stat_correlation( array $arr1, array $arr2 )

Parameters

Return Values

The stats_stat_correlation() function can return the Pearson correlation coefficient between arr1 and arr2, or false on failure.

Dependencies

This function was first introduced in statistics extension (PHP 4.0.0 and PEAR 1.4.0). We have used latest release of stats-2.0.3 (PHP 7.0.0 or newer and PEAR 1.4.0 or newer) for this tutorial

Example

In the following example, we compute the Pearson correlation coefficient of two data sets.

<?php
   var_dump(stats_stat_correlation(array(1, 2, 3), array(1, 2, 3)));
?>

Output

This will produce following result −

float(1)

Example

In the following example, we compute the Pearson correlation coefficient of two data sets.

<?php
   var_dump(stats_stat_correlation(array(1, 2, 3), array(1, 2, 1)));
?>

Output

This will produce following result −

float(0)

Example

Following is an error case. In the following example, we pass two arrays with unequal length. A warning is displayed in logs.

<?php
   // error cases
   var_dump(stats_stat_correlation(array(1, 2, 3), array(1, 2, 3, 4)));
?>

Output

This will produce following result and a warning in logs PHP Warning: stats_stat_correlation(): Unequal number of X and Y coordinates

bool(false)