Which of the following statements about scatterplots and $r$ (correlation) is correct?

• A. A positive $r$ (correlation) means that as one variable increases, the other variable also tends to increase.
• B. $r$ (correlation) implies causation between the two variables.
• C. A scatterplot with points forming a downward trend indicates a positive $r$ (correlation).
• D. If the points on a scatterplot are widely scattered with no pattern, the $r$ (correlation) is strong.

Answer: (A)

Verified step by step guidance

1. Understand the concept of correlation: Correlation measures the strength and direction of a linear relationship between two quantitative variables.
2. Recall that a positive correlation means that as one variable increases, the other variable tends to increase as well. This is visually represented in a scatterplot by points trending upward from left to right.
3. Recognize that correlation does not imply causation. Just because two variables are correlated does not mean one causes the other.
4. Know that a downward trend in a scatterplot indicates a negative correlation, not a positive one.
5. Understand that if points are widely scattered with no clear pattern, the correlation is weak or close to zero, not strong.