public regressionVariance ( number $x ) : number | ||
$x | number | |
return | number |
public function regressionVariance($x)
{
$X = $this->createDesignMatrix($x);
$⟮XᵀX⟯⁻¹ = $this->⟮XᵀX⟯⁻¹;
$M = $X->multiply($⟮XᵀX⟯⁻¹)->multiply($X->transpose());
return $M[0][0];
}