Which of the following relationship are usually identified as average effects?

Descriptive
Causal
Predictive
None of the mentioned

The correct answer is: B. Causal

A causal relationship is a relationship between two variables in which one variable is the cause of the other. For example, smoking is a cause of lung cancer.

A descriptive relationship is a relationship between two variables that describes how they are related, but does not imply that one variable causes the other. For example, there is a descriptive relationship between height and weight, but height does not cause weight.

A predictive relationship is a relationship between two variables in which one variable can be used to predict the other. For example, the number of hours you study can be used to predict your test score.

In the context of the question, the relationship between smoking and lung cancer is a causal relationship. Smoking causes lung cancer.

The other options are incorrect because they do not describe a causal relationship. Descriptive relationships do not imply that one variable causes the other. Predictive relationships can be used to predict one variable from the other, but they do not imply that one variable causes the other.