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Simpson's Paradox

A phenomenon in which a trend appears in different groups of data but disappears or reverses when the groups are combined.

Simpson's Paradox

In the 1970s, Berkeley University was accused of sexism because female applicants were less likely to be accepted than male ones. However, when trying to identify the source of the problem, they found that for individual subjects the acceptance rates were generally better for women than men. The paradox was caused by a difference in what subjects men and women were applying for. A greater proportion of the female applicants were applying to highly competitive subjects where acceptance rates were much lower for both genders.

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