What does correlation analysis measure between two quantitative variables?

Correlation analysis is a statistical tool that helps to determine the relationship between two quantitative variables. It provides insights into both the strength and direction of this relationship.

The strength of the relationship refers to how closely the two variables are related; this is typically expressed using a correlation coefficient, which can range from -1 to 1. A coefficient close to 1 indicates a strong positive relationship, whereas a coefficient close to -1 indicates a strong negative relationship.

The direction of the relationship indicates whether the two variables move in the same direction (positive correlation) or in opposite directions (negative correlation).

Thus, correlation analysis captures both of these critical aspects—strength and direction—making it a comprehensive measure of the relationship between quantitative variables. This is why the correct answer encompasses both components of the relationship rather than focusing exclusively on one aspect or attributing a cause-and-effect dynamic.