PHP | stats_cdf_uniform() Function

PHP stats_cdf_uniform() 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_cdf_uniform() Function.

The built-in stats_cdf_uniform() function is used to calculate any one parameter of the uniform distribution specified values for the others.

Syntax

Following below is the syntax to use this function -

float stats_cdf_uniform ( float $par1, float $par2, float $par3, int $which )


Parameter Details

Sr.NoParameterDescription
1

par1

The first parameter

2

par2

The second parameter

3

par3

The third parameter

4

which

The flag to determine what to be calculated


Return Value

This built-in function in PHP can return the CDF, its inverse, or one of its parameters of the uniform distribution. The kind of return value and parameters (par1, par2, and par3) are determined by which.

The following table list the return value and parameters by which.

  • CDF denotes cumulative distribution function.
  • x denotes the value of the random variable.
  • a denotes the lower bound of the uniform distribution.
  • b denotes the higher bound of the uniform distribution.

whichReturn valuepar1par2par3
1CDFxab
2xCDFab
3axCDFb
4bxCDFa

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 below, when which = 1, calculate P from (X, A, B).

  • P is the integral from 0 to X of the uniform distribution. Input range: [0, 1].
  • X is the upper limit of integration of the uniform density.
  • A is the first parameter of uniform density.
  • B is the second parameter of the uniform density.

<?php
   // which = 1 : calculate P from (X, A, B)
   var_dump(stats_cdf_uniform(2.5, 1, 3, 1));  // A <= X <= B
   var_dump(stats_cdf_uniform(0, 1, 3, 1));    // X < A
   var_dump(stats_cdf_uniform(4, 1, 3, 1));    // X > B
?>

Output

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

float(0.75) float(0) float(1)

Example2

In the following example below, when which = 2, calculate X from (P, A, B).

  • P is the integral from 0 to X of the uniform distribution. Input range: [0, 1].
  • X is the upper limit of integration of the uniform density.
  • A is the first parameter of uniform density.
  • B is the second parameter of the uniform density.

<?php
   // which = 2 : calculate X from (P, A, B)
   var_dump(stats_cdf_uniform(0.75, 1, 3, 2));
?>

Output

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

float(2.5)

Example3

In the following example below, when which = 3, calculate A from (P, X, B).

  • P is the integral from 0 to X of the uniform distribution. Input range: [0, 1].
  • X is the upper limit of integration of the uniform density.
  • A is the first parameter of uniform density.
  • B is the second parameter of the uniform density.

<?php
   // which = 3 : calculate A from (P, X, B)
   var_dump(stats_cdf_uniform(0.75, 2.5, 3, 3));
?>

Output

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

float(1)

Example4

In the following example below, when which = 4, calculate B from (P, X, A).

  • P is the integral from 0 to X of the uniform distribution. Input range: [0, 1].
  • X is the upper limit of integration of the uniform density.
  • A is the first parameter of uniform density.
  • B is the second parameter of the uniform density.

<?php
   // which = 4 : calculate B from (P, X, A)
   var_dump(stats_cdf_uniform(0.75, 2.5, 1, 4));
?>

Output

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

float(3)

Example5

Following is an error case. In the following example below which<1, warning message is displayed in logs.

<?php
   var_dump(stats_cdf_uniform(2.5, 1, 3, 0));  // which < 1
?>

Output

The above code will produce the following result and a warning in logs PHP Warning: stats_cdf_uniform(): Fourth parameter ought to be in the 1..4 range.

bool(false)

Example6

Following is an error case. In the following example below which>4, warning message is displayed in logs.

<?php
   var_dump(stats_cdf_uniform(2.5, 1, 3, 5));  // which > 4
?>

Output

The above code will produce the following result and a warning in logs PHP Warning: stats_cdf_uniform(): Fourth parameter ought to be in the 1..4 range.

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 PHP stats_cdf_weibull() 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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