1) We must know that for a regression line in the form [tex]Y=bX+a[/tex], the expression for the correlation coefficient (r) is:
[tex]b=r\cdot\dfrac{s_y}{s_x}\Longrightarrow r=\dfrac{b\cdot s_x}{s_y}\Longrightarrow r=\dfrac{3.46\cdot1.8}{7.2}\iff\boxed{r=0,865}\\\\\to\text{The answer is B.}[/tex]
[tex]2)~\text{The answer is B.}[/tex]
