Rock, Paper, Scissors

1 2 3 Shoot......I win!
So, today in class we played rock, paper, scissors! Math was involved, so don't worry and it was still fun. We worked in pairs and played 45 games of rock, paper, scissors. I was paired with Amber, enough said. Now, after each game we would record the outcomes and put tally marks in a matrix, like this one:

As you can see I'm pretty good at this game....not really. After calculating the experimental probability of me winning, which was 12 out of 45 ( we calculated that by looking at how many times I won over the total number of games we played) and the probability of Amber winning, which was 16 out of 45 (same process), Amber and I were pretty even throughout the games. Yet we both apparently liked paper! Based on our outcomes, you could say that the game rock, paper, scissors is fair but under the ideal circumstances the theoretical probabilities would all have to be 1 out of 3.  But ours was pretty close to fair.

Under the same idea circumstances you could take this game and analyze it using a tree diagram. The probability of playing/showing a rock, paper or scissor would all be one third. Now lets say you showed a rock for the first game, for the second game you have the same probability of playing/showing a rock, paper or scissor as the first game, one third. If the game rock, paper, scissors was repeated a large number of times, our experimental probabilities would approach a fixed number. This is called Bernoulli's Theorem or Law of Large Numbers.

I never knew the simple game of rock, paper, scissors could help you learn probability in your college level math class, but it can! Also, did you know that there are professional competitions for rock, paper, scissors? Check it out! Until next time, which will probably be tomorrow! :)

Lauren