Back to our example.

Is marital status independent of age in the nightclub sample?

If it is, P(S|U) = P(S)

P(S|U) = P(S?U)/P(U) = .55/.65 = .846

P(S) = .75, so P(S|U) ? P(S)

This tells us that a person is more likely to be single, if we know they’re under 30, than any one random person is likely to be single with no information about their age.

Previous slide

Next slide

Back to first slide

View graphic version