6.8 Features of r

• Independent of origin and scale
• \(-1 \le r \le 1\)
• \(r = \sqrt{b_{yx} \cdot b_{xy}}\) (Concerning GM of regression coeff)
• \(\frac{b_{yx}+b_{xy}}{2} \ge r\) (About AM)
• \(r = 0 \rightarrow\) no linear relationship