/**
* Returns the inverse survival function, the inverse of the sf
*
* @param float $x The test value
* @return float The value that gives an sf of $x
*/
public function isf($x)
{
return $this->calculator->getIsf($x, $this->df);
}
/**
* Returns the inverse survival function, the inverse of the sf
*
* @param float $x The test value
* @return float The value that gives an sf of $x
*/
public function isf($x)
{
return $this->calculator->getIsf($x, $this->df);
}