Which of the following is an accurate description of Simpson's paradox?



When groups of data are aggregated, an association can get stronger because of a confounding variable. That confounding variable is usually the number of observations in different groups of data.

When groups of data are combined, an association can get stronger because of a lurking variable. That lurking variable is usually the number of observations in the different groups of data.

When groups of data are separated, an association can get stronger because of a lurking variable. That lurking variable is usually the number of observations in the different groups of data.

When separate groups of data are combined, an association can reverse direction because of a lurking variable that was lost when the different groups of data were lumped together.

I was thinking option A

Option A is close, but not entirely accurate. The correct answer is option D: When separate groups of data are combined, an association can reverse direction because of a lurking variable that was lost when the different groups of data were lumped together.

Simpson's paradox is a statistical phenomenon where the direction of an association between two variables changes or reverses when data is aggregated or combined from different groups. This paradox occurs when a lurking variable, which is a variable that is not initially accounted for or controlled for in the analysis, affects the relationship between the two variables when the groups are combined. This lurking variable can lead to misleading or contradictory conclusions if not properly accounted for. Therefore, option D accurately describes Simpson's paradox.

Option A is not an accurate description of Simpson's paradox. Simpson's paradox refers to a phenomenon where an association observed in different groups of data reverses or disappears when the groups are combined or aggregated. This reversal or disappearance is not caused by a confounding variable, but rather by a hidden or lurking variable that affects the relationship between the variables being studied. So, the correct option would be D: "When separate groups of data are combined, an association can reverse direction because of a lurking variable that was lost when the different groups of data were lumped together."