Dr. Guinea was studying the relation between the amount of caffeine intake and people's performance on a difficult task. He found out that as the amount of caffeine intake increases, the time to finish the task first decreases, and then increases. If he used the data to fit a linear regression model, which assumption would likely be violated?
A) Independence
B) Homogeneity
C) Linearity
D) Normality
E) Fixed X

Question

Quizplus · Accepted Answer

The description of the relationship between caffeine intake and task performance (first decreases, then increases) suggests a non-linear relationship. A linear regression model assumes a linear relationship between the independent and dependent variables, so this assumption would be violated.

Dr Guinea Was Studying the Relation Between the Amount of Caffeine