Brandon has discovered that on days that he either doesn't exercise or overdoes his exercising he feels extremely tired in the evening. On days that he does a moderate amount of exercise he feels quite refreshed in the evenings. Which of the following best describes the relationship between Brandon's exercising and how tired he feels?
A) highly positively correlated
B) moderately negatively correlated
C) linear
D) nonlinear
E) moderately positively correlated

Question

Quizplus · Accepted Answer

The relationship between Brandon's exercising and his tiredness is nonlinear because his energy levels are low both when he exercises too little and too much, but are higher with a moderate amount of exercise. This indicates a curve rather than a straight line, hence nonlinear.

Brandon Has Discovered That on Days That He Either Doesn't