In statistics, what is the mathematical technique used to investigate an association between two variables?

In statistics, what is the mathematical technique used to investigate an association between two variables?

• A. Regression
• B. Correlation
• C. Causation
• D. Sampling

Answer: (B)

Correlation quantifies whether and how two quantitative variables vary together. It captures both direction and strength: if the variables tend to rise together, the association is positive; if one tends to fall as the other rises, it's negative. The correlation coefficient ranges from -1 to 1, where values near 1 or -1 indicate a strong linear relationship and values near 0 suggest little or no linear association. For linear, continuous data, Pearson correlation is the standard measure; for data that aren’t normally distributed or are ordinal, Spearman’s rho (or Kendall’s tau) is appropriate. This approach focuses on the presence and strength of association, not causation. Regression, while related, is about predicting one variable from another and implies a directional relationship, which goes beyond simply establishing an association. Sampling relates to how data are collected, not specifically to measuring association.

Correlation quantifies whether and how two quantitative variables vary together. It captures both direction and strength: if the variables tend to rise together, the association is positive; if one tends to fall as the other rises, it's negative. The correlation coefficient ranges from -1 to 1, where values near 1 or -1 indicate a strong linear relationship and values near 0 suggest little or no linear association. For linear, continuous data, Pearson correlation is the standard measure; for data that aren’t normally distributed or are ordinal, Spearman’s rho (or Kendall’s tau) is appropriate. This approach focuses on the presence and strength of association, not causation. Regression, while related, is about predicting one variable from another and implies a directional relationship, which goes beyond simply establishing an association. Sampling relates to how data are collected, not specifically to measuring association.