# 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 )`

## Parameter Details

Sr.NoParameterDescription
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)`

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.

Feel free to ask your questions where necessary and we will attend to them as soon as possible. If this tutorial was helpful to you, you can use the share button to share this tutorial.

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