Final answer:
The statement that correlation measures non-linear relationships is false. Correlation assesses linear relationships, and its strength is weakest when closest to 0. A correlation of -.90 indicates a stronger relationship than -.50.
Step-by-step explanation:
The statement "Correlation does measure non-linear relationships" is false. Correlation, specifically the Pearson correlation coefficient, measures the strength and direction of a linear relationship between two variables. Non-linear relationships require other types of analysis to properly assess the relationship.
A positive correlation does not necessarily mean there are health benefits to the variable under investigation; it simply indicates that as one variable increases, the other tends to increase as well. To determine health benefits, one must look beyond correlation to establish causation, which cannot be inferred from correlation alone. This principle is encapsulated in the sentence: "Correlation does not imply causation."
In terms of the strength of relationships, the correlation coefficient indicates the weakest relationship when it is closest to 0. Conversely, when comparing correlation coefficients of -0.90 and -0.50, a coefficient of -.90 indicates the strongest relationship between two variables. This shows a stronger linear association, regardless of whether the relationship is positive or negative.