Contingent probability

Hi
what does contingent probability mean?
can you plz help how he came to this conclusion? that if the two criteria are not independent, and if P(B)=0.50, then the f the two criteria are not independent, and if P (B ) = 0.50, then the contingent probability of P (A | B ) is greater than 0.50 of P(A|B) is greater than 0.50.

The easiest way to see this is to let criterion A be the same as criterion B. Clearly, they’re positively related. In this case, P(A|B) = 1.0, and P(AB) = 0.5 > 0.25.