How is the strength of the relationship in a correlation typically assessed from a scatterplot?

How is the strength of the relationship in a correlation typically assessed from a scatterplot?

• A. The slope of the line determines strength
• B. The tighter the points cluster around a straight line, the closer r is to 1, and the stronger the relationship
• C. The sign of the correlation determines strength
• D. The sample size determines strength

Answer: (B)

The strength of a linear relationship is judged by how tightly the data points fall along a straight line. When the points cluster closely around a straight line, the correlation coefficient has a magnitude near 1, indicating a strong linear relationship (whether the line slopes up or down is about direction, not strength). If the points are widely scattered, the magnitude of the correlation is near 0, indicating a weak linear relationship. The slope tells you the rate of change, but not how strong the relationship is. Sample size affects how precisely you estimate the strength, not the strength itself. So, visually, tighter clustering around a straight line signals a stronger relationship, with the strength reflected in how close the correlation is to ±1.

The strength of a linear relationship is judged by how tightly the data points fall along a straight line. When the points cluster closely around a straight line, the correlation coefficient has a magnitude near 1, indicating a strong linear relationship (whether the line slopes up or down is about direction, not strength). If the points are widely scattered, the magnitude of the correlation is near 0, indicating a weak linear relationship. The slope tells you the rate of change, but not how strong the relationship is. Sample size affects how precisely you estimate the strength, not the strength itself. So, visually, tighter clustering around a straight line signals a stronger relationship, with the strength reflected in how close the correlation is to ±1.