For example, if we know that somebody would be holding a safety net somewhere between the balcony of the 10th floor and the pavement, then we know that the probability of survival would be much, much, higher than 1%!
Also, if we know that some forest is in prime tourist development area, we know that its risk to fire is much much higher than the prior probability we computed before.
We use the conditional probabilities to express this. We write p(A|B) to mean probability of A happening, given that B happened.
Prior Probability
Conditional Probability
P(forest A will be burned)
P(forest A will be burned given that forest A is in Attica.)
