The correlation coefficient r equal to 1 indicates what?

The correlation coefficient r equal to 1 indicates what?

• A. A perfect correlation
• B. No correlation
• C. A weak correlation
• D. A negative correlation

Answer: (A)

The correlation coefficient measures how strongly and in what direction two variables move together along a straight line. When it equals 1, every observed point falls exactly on a straight line with positive slope, meaning the variables have a perfect positive linear relationship. As one variable increases, the other increases in exact proportion, leaving no scatter. This implies you could predict one variable from the other with perfect accuracy in a linear model. In contrast, values near 0 indicate little or no linear relationship, and values near -1 indicate a perfect negative linear relationship.

The correlation coefficient measures how strongly and in what direction two variables move together along a straight line. When it equals 1, every observed point falls exactly on a straight line with positive slope, meaning the variables have a perfect positive linear relationship. As one variable increases, the other increases in exact proportion, leaving no scatter. This implies you could predict one variable from the other with perfect accuracy in a linear model. In contrast, values near 0 indicate little or no linear relationship, and values near -1 indicate a perfect negative linear relationship.