stats_cdf_f

(PECL stats >= 1.0.0)

stats_cdf_f — Calculates any one parameter of the F distribution given values for the others.

说明

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

Returns the cumulative distribution function, its inverse, or one of its parameters, of the F distribution. The kind of the return value and parameters (par1, par2, and par3) are determined by which.

The following table lists the return value and parameters by which. CDF, x, d1, and d2 denotes cumurative distribution function, the value of the random variable, and the degree of freedoms of the F distribution, respectively.

Return value and parameters
which Return value par1 par2 par3
1 CDF x d1 d2
2 x CDF d1 d2
3 d1 x CDF d2
4 d2 x CDF d1

参数

par1

The first parameter

par2

The second parameter

par3

The third parameter

which

The flag to determine what to be calculated

返回值

Returns CDF, x, d1, or d2, determined by which.

User Contributed Notes

brjann (theat) gmail (thedot) com 06-Oct-2007 03:18
Input  and return values of stats_cdf_t depends on the $which-parameter:
<?php
function get_t_p($t, $df){
   return stats_cdf_t($t, $df, 1);
}

function get_t_t($p, $df){
   return stats_cdf_t($p, $df, 2);
}

function get_t_df($p, $t){
   return stats_cdf_t($p, $t, 3);
}
?>