Chapter 4, Problem AP1.5CPT

To determine

To select the best option from the multiple choice question according to the given question.

Answer to Problem AP1.5CPT

Option (a) is correct.

Explanation of Solution

Given prediction equation:

Predicted tail length $=20+3\times \text{weight}$ .

Thus, the option (a) is not correct as the slope is the coefficient of weight and thus is $3$ . This then also means that the predicted tail length increases by $3$ mm for each additional gram in weight.

Option (b) is correct, as replace weight in the prediction equation with $\text{38}$ :

Predicted tail length $\begin{array}{l}=20+3\times 38\\ =134\end{array}$

Thus the predicted tail length is $134$ mm.

Option (c) is also correct as the slope is three and thus positive which then means that the correlation is also positive.

Option (d) is correct as if the measurements are in cm instead of mm, all values in the prediction equation need to be divided by $10$ and the slope will become $0.3$ .

Option (e) is correct as replace weight in the prediction equation with $29$ :

Predicted tail length $\begin{array}{l}=20+3\times 29\\ =107\end{array}$

The residual is the actual value decreased by the predicted value i.e.

Residual $\begin{array}{l}100-107\\ =-7\end{array}$

Thus, we conclude that we will click on the option (a).