PHP - Stats Dens f() Function

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Definition and Usage

The stats_dens_f() function is a probability density function of the F distribution.

Syntax

float stats_dens_f( float $x, float $dfr1, float $dfr2 )

Parameters

Return Values

The stats_dens_f() function can return the probability density at x, where the random variable can follow the F distribution of which the degree of freedoms are dfr1 and dfr2, or false for 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 probability density for each x.

<?php
   // check for each x
   foreach (range(0, 3, 0.5) as $x) {
      var_dump(round(stats_dens_f($x, 3, 2), 6));
      echo "<br>";
   }
?>

Output

This will produce following result −

  float(0)
  float(0.48097)
  float(0.278855)
  float(0.177241)
  float(0.121785)
  float(0.088606)
  float(0.067279)

Example

In the following example, we compute probability density for each dfr1.

<?php
   // check for each dfr1
   foreach (range(0.5, 3, 0.5) as $dfr1) {
      var_dump(round(stats_dens_f(1, $dfr1, 2), 6));
      echo "<br>";
   }
?>

Output

This will produce following result −

  float(0.133748)
  float(0.19245)
  float(0.227008)
  float(0.25)
  float(0.266463)
  float(0.278855)

Example

In the following example, we compute probability density for each dfr2.

<?php
   // check for each dfr2
   foreach (range(0.5, 3, 0.5) as $dfr2) {
      var_dump(round(stats_dens_f(1, 3, $dfr2), 6));
      echo "<br>";
   }
?>

Output

This will produce following result −

  float(0.139548)
  float(0.206748)
  float(0.249129)
  float(0.278855)
  float(0.301042)
  float(0.31831)