What term describes a relationship where variables are related but not linear?

What term describes a relationship where variables are related but not linear?

• A. Linear
• B. Categorical
• C. Nonlinear or curvilinear
• D. Random

Answer: (C)

The main idea is recognizing the difference between linear and nonlinear relationships. A linear relationship shows a constant rate of change and appears as a straight line on a scatterplot. When the pattern isn’t a straight line, the relationship is nonlinear (also called curvilinear). In nonlinear or curvilinear relationships, the way one variable changes depends on where you are along the range, so the rate of change shifts and the plot curves. This is why nonlinear or curvilinear is the best description for a relationship where the variables are related but not linear, such as a curve that rises quickly and then levels off, or one that forms a U-shape. A linear description would be inappropriate here because it would imply a straight-line pattern. A categorical description isn’t about the pattern of a relationship between continuous variables, and random would imply no pattern at all.

The main idea is recognizing the difference between linear and nonlinear relationships. A linear relationship shows a constant rate of change and appears as a straight line on a scatterplot. When the pattern isn’t a straight line, the relationship is nonlinear (also called curvilinear). In nonlinear or curvilinear relationships, the way one variable changes depends on where you are along the range, so the rate of change shifts and the plot curves. This is why nonlinear or curvilinear is the best description for a relationship where the variables are related but not linear, such as a curve that rises quickly and then levels off, or one that forms a U-shape. A linear description would be inappropriate here because it would imply a straight-line pattern. A categorical description isn’t about the pattern of a relationship between continuous variables, and random would imply no pattern at all.