PHP | stats_cdf_noncentral_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_cdf_noncentral_f() Function.

The PHP stats_cdf_noncentral_f() function is used to calculate any one parameter of non-central f distribution specified values for the others.

Syntax

Following below is the syntax to use this function -

float stats_cdf_noncentral_f( float $par1, float $par2, float $par3, float $par4, int $which )

READ: PHP | stats_cdf_noncentral_chisquare() Function

Parameter Details

Sr.No	Parameter	Description
1	par1	The first parameter
2	par2	The second parameter
3	par3	The third parameter
4	par4	The fourth parameter
5	which	The flag to determine what to be calculated

Return Value

This built-in function can return the CDF, its inverse, or one of its parameters of the non-central f distribution. The kind of the return value and parameters (par1, par2, par3, and par4) 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 random variable.

• nu1, nu2 denotes the degree of freedom of the distribution.

• lambda denotes the non-centrality parameter of the distribution.

which	Return value	par1	par2	par3	par4
1	CDF	x	nu1	nu2	lambda
2	x	CDF	nu1	nu2	lambda
3	nu1	x	CDF	nu2	lambda
4	nu2	x	CDF	nu1	lambda
5	lambda	x	CDF	nu1	nu2

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 (F, DFN, DFD, PNONC).

• P is the integral from 0 to F of the non-central f-density.

• F is the upper limit of integration of the non-central f-density.

• DFN is the degree of freedom of the numerator sum of squares.

• DFD is the degree of freedom of the denominator sum of squares.

• PNONC is the non-centrality parameter of the non-central f-density.

<?php
   // which = 1 : calculate P from (F, DFN, DFD, PNONC)
   var_dump(round(stats_cdf_noncentral_f(5, 2, 3, 4, 1), 6));
?>

Output

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

float(0.650459)

Example2

In the following example below, when which = 2, calculate F from (P, DFN, DFD, PNONC).

• P is the integral from 0 to F of the non-central f-density.

• F is the upper limit of integration of the non-central f-density.

• DFN is the degree of freedom of the numerator sum of squares.

• DFD is the degree of freedom of the denominator sum of squares.

• PNONC is the non-centrality parameter of the non-central f-density.

<?php
   // which = 2 : calculate F from (P, DFN, DFD, PNONC)
   var_dump(round(stats_cdf_noncentral_f(0.650459043, 2, 3, 4, 2), 6));
?>

Output

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

float(5)

Example3

In the following example below, when which = 3, calculate DFN from (P, F, DFD, PNONC).

• P is the integral from 0 to F of the non-central f-density.

• F is the upper limit of integration of the non-central f-density.

• DFN is the degree of freedom of the numerator sum of squares.

• DFD is the degree of freedom of the denominator sum of squares.

• PNONC is the non-centrality parameter of the non-central f-density.

<?php
   // which = 3 : calculate DFN from (P, F, DFD, PNONC)
   var_dump(round(stats_cdf_noncentral_f(0.650459043, 5, 3, 4, 3), 6));
?>

Output

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

float(2)

Example4

In the following example below, when which = 4, calculate DFD from (P, F, DFN, PNONC).

• P is the integral from 0 to F of the non-central f-density.

• F is the upper limit of integration of the non-central f-density.

• DFN is the degree of freedom of the numerator sum of squares.

• DFD is the degree of freedom of the denominator sum of squares.

• PNONC is the non-centrality parameter of the non-central f-density.

<?php
   // which = 4 : calculate DFD from (P, F, DFN, PNONC)
   var_dump(round(stats_cdf_noncentral_f(0.650459043, 5, 2, 4, 4), 6));
?>

Output

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

float(3)

Example5

In the following example below, when which = 5, calculate PNONC from (P, F, DFN, DFD).

• P is the integral from 0 to F of the non-central f-density.

• F is the upper limit of integration of the non-central f-density.

• DFN is the degree of freedom of the numerator sum of squares.

• DFD is the degree of freedom of the denominator sum of squares.

• PNONC is the non-centrality parameter of the non-central f-density.

<?php
   // which = 5 : calculate PNONC from (P, F, DFN, DFD)
   var_dump(round(stats_cdf_noncentral_f(0.650459043, 5, 2, 3, 5), 6));
?>

Output

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

float(4)

Example6

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

<?php
   var_dump(round(stats_cdf_noncentral_f(1, 2, 3, 4, 0), 6));      // which < 1
?>

Output

The above code will produce the following result and a warning in logs PHP Warning: stats_cdf_noncentral_f(): Fourth parameter should to be in the 1..5 range.

float(0)

Example7

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

<?php
   var_dump(round(stats_cdf_noncentral_f(1, 2, 3, 4, 6), 6));      // which > 5
?>

Output

The above code will produce the following result and a warning in logs PHP Warning: stats_cdf_noncentral_f(): Fourth parameter should to be in the 1..5 range.

float(0)

READ: PHP | stats_cdf_negative_binomial() 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 stats_cdf_noncentral_t() Function in PHP.

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