What kind of correlation would enable Heather to make the most accurate prediction about her life expectancy based on her waist circumference?

A strong positive correlation would enable Heather to make the most accurate prediction about her life expectancy based on her waist circumference. This type of correlation indicates that as one variable increases, the other variable also increases in a consistent and predictable manner.

In this context, a strong positive correlation between waist circumference and life expectancy would suggest that larger waist circumferences are associated with lower life expectancy, which is a significant public health concern. Therefore, a strong positive correlation would mean that predicting life expectancy from waist circumference is reliable and meaningful.

In contrast, weak correlations, whether negative or positive, indicate a weaker, less reliable relationship between the two variables. This would result in less accurate predictions about life expectancy on the basis of waist circumference, as the relationship is not strong enough to support confident forecasting.