Why, sometimes, are some of the judges marks on Olympic Diving not counted?

Question

I don't know the rules of diving, could someone explain why sometimes the lowest marks or the highest marks aren't counted?

Answer 1

Its not sometimes...its everytime... the highest and lowest marks are discarded and the rest are averaged out to the score that the diver receives.

Answer 2

I believe the highest and lowest marks are removed... this is to prevent cheating by judges who favorr a certain competitor.

Answer 3

Always and I believe it is in every event the highest and lowest are tossed out and only the scores in the middle count.  This happens so a really low or a really high score does not skew the average.