Chapter 4.5, Problem 28E

To determine

To verify: The claim of friend regarding weakening of correlation.

Answer to Problem 28E

Yes, the claim made by the friend is correct.

Explanation of Solution

Given information: Table and equation of exercise $27$ is to be considered.

Calculation:

Equation is $y=-0.083x+3.83$ ,

Substituting $x=2$ in the above equation.

  $\begin{array}{l}y=-0.083(2)+3.83\\ y=3.664\end{array}$

According to the equation, grade point average in given case should be $3.664$ ,

But as per statement, grade point average is $2.4$ ,

As the actual grade point average is less than the one derived from equation, such a large difference of $\begin{array}{l}3.664-2.4=1.264\end{array}$ will definitely lead to a decrease in correlation coefficient.

Thus, friend is correct.