Berkson's paradox

An interesting paradox coming from the Selection bias regarding Collider variable. One of the best examples would be the attractiveness and talent as Wikipedia explains:

In figure 1, assume that talent and attractiveness are uncorrelated in the population. In figure 2, someone sampling the population using celebrities may wrongly infer that talent is negatively correlated with attractiveness, as people who are neither talented nor attractive do not typically become celebrities.

A Numberphile episode by Hannah Fry explains this with books that are adapted in films:

Here is other nice examples: Collider Bias (Berkson’s paradox): how ‘censored’ data leads to flawed conclusions

See also Simpson’s paradox.