Paxman, you idiot

More shocking ignorance from Paxman on University challenge, again leading to him claiming that a valid answer was incorrect. This time, from the program on 22nd October 2007:

Paxman: In statistics, data that are binomially distributed, individual values may be placed in one of two mutually exclusive categories so that the sum of the probabilities of occurring in the categories is what value?
Liverpool Ling: Er... unity.
Paxman: No, it's 1, or 100%
LL: (rolls eyes)

Something should be done!