YSK: The Simpson's Paradox is a phenomenon where a trend shows up in one group, then disappears when combined with another. (Laymen's terms--there is a more extensive definition).
from /r/YouShouldKnow
YSK: 辛普森悖论是一种现象，一种趋势在一个群体中出现，然后与另一个群体结合后消失。(外行的说法--有一个更广泛的定义)。