A forester would like to estimate the diameter of maple trees based on age. She gathers data from trees that have been cut and plots their diameters (in inches) against their ages (in years). She fits a linear model and both the scatterplot and residual plots are shown below. Which of the following is true?
A) If we used this model to predict the diameter of a maple tree that is 50 years old, the predicted value would be too low.
B) If we used this model to predict the diameter of a maple tree that is 50 years old, the predicted value would be quite reliable.
C) Re-expressing these data by taking the logarithm of age would not improve this model.
D) If we used this model to predict the diameter of a maple tree that is 50 years old, the predicted value would be too low or it would be too high.
E) If we used this model to predict the diameter of a maple tree that is 50 years old, the predicted value would be too high, furthermore, re-expressing these data by taking the logarithm of age would improve this model.

Question

A forester would like to estimate the diameter of maple trees based on age. She gathers data from trees that have been cut and plots their diameters (in inches) against their ages (in years). She fits a linear model and both the scatterplot and residual plots are shown below.   Which of the following is true?
A) If we used this model to predict the diameter of a maple tree that is 50 years old, the predicted value would be too low. 
B) If we used this model to predict the diameter of a maple tree that is 50 years old, the predicted value would be quite reliable. 
C) Re-expressing these data by taking the logarithm of age would not improve this model. 
D) If we used this model to predict the diameter of a maple tree that is 50 years old, the predicted value would be too low or it would be too high. 
E) If we used this model to predict the diameter of a maple tree that is 50 years old, the predicted value would be too high, furthermore, re-expressing these data by taking the logarithm of age would improve this model.

Quizplus · Accepted Answer

The Answer of A forester would like to estimate the diameter of maple trees based on age. She gathers data from trees that have been cut and plots their diameters (in inches) against their ages (in years). She fits a linear model and both the scatterplot and residual plots are shown below.   Which of the following is true?
A) If we used this model to predict the diameter of a maple tree that is 50 years old, the predicted value would be too low. 
B) If we used this model to predict the diameter of a maple tree that is 50 years old, the predicted value would be quite reliable. 
C) Re-expressing these data by taking the logarithm of age would not improve this model. 
D) If we used this model to predict the diameter of a maple tree that is 50 years old, the predicted value would be too low or it would be too high. 
E) If we used this model to predict the diameter of a maple tree that is 50 years old, the predicted value would be too high, furthermore, re-expressing these data by taking the logarithm of age would improve this model.

A Forester Would Like to Estimate the Diameter of Maple