One of those drafts I should expand…
Elo rating system
A few days ago, a chess tournament took place. In the quarter of finals, MVL, rated 2860, played against Wesley So, rated 2741. Who should win ?
The Elo rating system answers this question, and gives a probability:
wesley_so = 2741 mvl = 2860 D = mvl - wesley_so probability_mvl_wins = 1/(1+10 ** (-D/400)) probability_so_wins = 1 - probability_mvl_wins print(probability_mvl_wins)
$ python mvl-wesley-so.py 0.6648579785547648
MVL should win a game with a probability of 66%. This is not what happened though, So won
There are many interesting applications. One I liked is how to estimate the winner of a tournament.
The Bradley-Terry model
I came across a very interesting article about ranking chocolates. They compared 2 chocolates, and choose a winner. After many pairwise comparisons, it is possible to use the Bradley-Terry Model in order to assign each chocolate a score. This is well explained in the wikipedia page, here is an example with numbers about how to compute the scores
See a typo ? You can suggest a modification on Github.