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# PHP | stats_dens_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_dens_f() Function.

The built-in stats_dens_f() function is the probability density function of f distribution.

## Syntax

Following below is the syntax to use this function -

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

## Parameter Details

Sr.NoParameterDescription
1

x

The value at which the probability density is calculated

2

dfr1

The degree of freedom of the distribution.

3

dfr2

The degree of freedom of the distribution.

## Return Value

This built-in function returns the probability density at x, where the random variable can follow the f distribution of which the degree of freedoms are dfr1 and dfr2, else false on failure.

## 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

The following example below computes the 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

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

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

### Example2

The following example below computes the 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

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

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

### Example3

The following example below computes the 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

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

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

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 PHP stats_dens_gamma() 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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Thanks for reading and bye for now.