(PECL stats >= 1.0.0)
stats_cdf_t — Calculates any one parameter of the T distribution given values for the others.
$par1
, float $par2
, int $which
)This function is currently not documented; only its argument list is available.
par1
par2
which
In order to match the output of this function with Excel's TDIST function, you must take 1 - the value. For example, for a two-tailed T-distribution for x=4 and degrees of freedom=2, the formula would be:
(1 - stats_cdf_t(4, 2, 1)) * 2
For a single tail, do not include the multiply by 2 portion.
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);
}
?>
