The Lizard-Spock Expansion - S2-E8
Corrected entry: Sheldon suggests Rock, Paper, Scissors, Lizard, Spock as an alternative to Rock, Paper, Scissors because "Anecdotal evidence suggests that in the game of rock-paper-scissors, players familiar with each other will tie 75 to 80% of the time due to the limited number of outcomes." As a devout scientist, Sheldon would know that anecdotal evidence is no basis for reaching a conclusion because it is based on individual experience and subject to bias. (00:00:30)
Correction: Presumably the "anecdotal evidence" is his own experience; within his group of friends they tie 75-80% of the time.