Chapter 3.2, Problem 77E

To determine

To find out what affect will this addition have on the correlation and the slope of the least-squares regression line.

Answer to Problem 77E

The option (b) is the correct option.

Explanation of Solution

It is given that x be as Arm span and y be the height.

And also,

  $\widehat{y}=6.4+0.93x$

  $\begin{array}{l}x=120\\ y=118\end{array}$

Now, let us find the predicted value as:

  $\begin{array}{l}\widehat{y}=6.4+0.93x\\ =6.4+0.93(120)\\ =118\end{array}$

Thus the predicted value is same as the actual value, which means the point will lie on the regression line. Thus, it makes the data more linear. And therefore the correlation will increase. And the regression line will not be affected by this point and therefore the slope will remain the same. Thus, the option (b) is the correct option.