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# PHP | stats_rand_gen_ibinomial_negative() Function

Hello folks! welcome back to a new edition of our tutorial on PHP. In this tutorial guide, we are going to be discussing briefly about the stats_rand_gen_ibinomial_negative() function.

The stats_rand_gen_ibinomial_negative() function generates random deviate from the negative binomial distribution.

## Syntax

Following below is the syntax to use this function -

`int stats_rand_gen_ibinomial_negative( int \$n, float \$p )`

## Parameter Details

Sr.NoParameterDescription
1

n

The number of success

2

p

The success rate

## Return Value

It returns a random deviate from negative binomial distribution where the number of success and the success rate is "n" and "p" respectively.

## 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

In the following example, we compute the random deviation from the given negative binomial distribution where the number of success is 2, and the success rate is 0.5 -

```<?php
var_dump(is_int(stats_rand_ibinomial_negative(2, 0.5)));
?>```

#### Output

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

`bool(true)`

### Example2

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

```<?php
// error cases
var_dump(stats_rand_ibinomial_negative(-1, 0.5));   // n < 0
?>```

#### Output

The above code will produce the following result and a warning in logs PHP Warning: stats_rand_ibinomial_negative(): n < 0. n: -1

`bool(false)`

### Example3

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

```<?php
// error cases
var_dump(stats_rand_ibinomial_negative(1, -0.1));   // pp < 0
?>```

#### Output

The above code will produce the following result and a warning in logs PHP Warning: stats_rand_ibinomial_negative(): p is out of range. p: -1E-1

`bool(false)`

### Example4

Following example below is an error case. In the following example, we have passed pp > 1. A warning is shown in logs -

```<?php
// error cases
var_dump(stats_rand_ibinomial_negative(1, 1.1));    // pp > 1
?>```

#### Output

The above code will produce the following result and a warning in logs PHP Warning: stats_rand_ibinomial_negative(): p is out of range. p: 1E+0.

`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 stats_rand_gen_int() Function.

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