Which characteristic of data can be determined using Pearson's Correlation Coefficient?

• A. It measures the ordinal relationship between two variables
• B. It measures the degree of relationship using rank order of values
• C. It measures the strength and direction of a linear relationship
• D. It measures the confidence level showing relevance and preciseness of the information

Answer: (C)

Pearson's correlation coefficient is used to quantify how strongly and in what direction two continuous variables relate in a linear way. The value ranges from -1 to 1: values near 1 indicate a strong positive linear relationship, values near -1 indicate a strong negative linear relationship, and values near 0 suggest little to no linear association. This measure specifically captures linear relationships between interval/ratio data and can be affected by outliers or by nonlinear patterns (in which case the linear index may be misleading). For ordinal data or relationships based on ranks, a different measure like Spearman's rho is used, and while you can test the significance of the correlation, the coefficient itself expresses the strength and direction of the linear relationship.