In baseball a player pitches a ball from the mound to a catcher behind the plate A pitch that passes over the plate above the batter s knees and below his chest is a strike All other pitches are balls provided the batter does not swing at them or hit them foul The table below breaks a sample number of pitches into strikes and balls over the plate and not over the plate Over plate Event C Not over plate Event D Strike Event A 10 0 Ball Event B 5 20 Which conditional probability below is either inaccurately described or inaccurately calculated The probability that a pitch not over the plate is a strike is zero So P AID 0 The probability that a pitch not over the plate is a ball is 1 So P BID 1 The probability that a pitch over the plate is a strike is 10 15 So O The probability that a pitch over the plate is a ball is 5 10 So P BIC 0 5