The regression coefficient of Y on X:
(a) bxy = \(\frac{N\Sigma\,dxdy-(\Sigma\,dx)(\Sigma\,dy)}{N\Sigma\,dy^2-(\Sigma\,dy)^2}\)
(b) byx = \(\frac{N\Sigma\,dxdy-(\Sigma\,dx)(\Sigma\,dy)}{N\Sigma\,dy^2-(\Sigma\,dy)^2}\)
(c) byx = \(\frac{N\Sigma\,dxdy-(\Sigma\,dx)(\Sigma\,dy)}{N\Sigma\,dx^2-(\Sigma\,dx)^2}\)
(d) bxy = \(\frac{N\Sigma\,xy-(\Sigma\,x)(\Sigma\,y)}{\sqrt{N\Sigma\,x^2-(\Sigma\,x)^2}\times\sqrt{N\Sigma\,y^2-(\Sigma\,y)^2}}\)