PHP | stats_rand_gen_f() Function

Hello folks! welcome back to a new edition of our tutorial on PHP. In this tutorial guide, we are going to be studying about the PHP stats_rand_gen_f() Function.

The built-in PHP stats_rand_gen_f() function is used to generate a random deviate from the F distribution.

Syntax

Following below is the syntax to use this function -

float stats_rand_gen_f( float $dfn, float $dfd )

READ: PHP | stats_rand_gen_exponential() Function

Parameter Details

Sr.No	Parameter	Description
1	dfn	The degrees of freedom in the numerator
2	dfd	The degrees of freedom in the denominator

Return Value

This function generates a random deviate from the F distribution with a "dfn" degree of freedom in the numerator, and then "dfd" degree of freedom in the denominator. This built-in function can generate a ratio of chi-square variates.

Dependencies

This built-in function was first introduced in statistics extension (PHP version 4.0.0 and PEAR v1.4.0). In this tutorial guide, we used the latest release of stats-2.0.3 (PHP v7.0.0 or newer and PEAR version 1.4.0 or newer).

Example1

Following example computes the random deviation from the F distribution -

<?php
   var_dump(is_float(stats_rand_gen_f(3, 2)));
?>

Output

When the above code is executed, it will produce the following result -

bool(true)

Example2

The following below is an error case, in the below example, we have passed dfn < 0. A warning is shown in logs -

<?php
   // error cases
   var_dump(stats_rand_gen_f(-0.1, 2));    // dfn < 0
?>

Output

The above code will produce the following result and a warning in logs PHP Warning: stats_rand_gen_f(): Degrees of freedom non-positive. DFN value: -1.000000E-1 DFD value: 2.000000E+0

bool(false)

Example3

The following below is an error case. In the below example, we have passed dfr < 0. A warning is shown in logs -

<?php
   // error cases
   var_dump(stats_rand_gen_f(3, -0.1));    // dfr < 0
?>

Output

The above code will produce the following result and a warning in logs PHP Warning: stats_rand_gen_f(): Degrees of freedom non-positive. DFN value: 3.000000E+0 DFD value: -1.000000E-1

bool(false)

READ: PHP | stats_rand_gen_beta() Function

Alright guys! This is where we are going to be rounding up for this tutorial post. In our next tutorial, we are going to be discussing about the built-in stats_rand_gen_funiform() Function.

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