Question

1. What is a correlation? Give an example.

2. What does a correlation tell us about the relationship between two variables?

3. Explain why correlation does not mean causation.

Answer 1

1. A correlation is a statistic that measures the degree to which two variables are related to each other. For example, weight and height are positively correlated variables.

2. A correlation tells us the strength and direction of relationship between two variables. The strength indicates how likely one variable is likely to change when the other undergoes a change. The direction indicates whether both the variables change in the same direction or in the opposite direction.

3. Correlation does not mean causation because correlation simply indicates if one variable changes with change in another variable. If two variables X and Y are correlated, it could imply any of the following: X causes Y; Y causes X; a third variable mediates the relationship between X and Y; or the relationship is only a coincidence.