THE PLAYOFFS AS AN EXAMPLE OF SMALL SAMPLES.
THE PLAYOFFS AS AN EXAMPLE OF SMALL SAMPLES. It takes 162 games to determine the teams that make the major league baseball playoffs. The World Series is a maximum of 7 games.
Nick had a good analysis of how the playoffs and World Series illustrate the problems of small samples in this post on the Catbird Seat blog. Here is an excerpt from Nick’s post:
“What does it mean to say, ‘Small sample size?’
“I’ve only ever taken one formal statistics class, and it was over 10 years ago, but I still remember the first lesson very vividly. Our teacher divided the class into two groups. One half of the class was supposed to flip a coin 30 times and document the results. The other half was to write down a sequence of 30 heads or tails and try to make it look like it was the actual, random results of a coin flip.
“Our teacher guessed which ones were real and which ones were fake with, if memory serves, 100% accuracy. The reason is that the people who actually flipped coins wound up with really long streaks of heads and tails – 7 in a row or more. Meanwhile, the ones who were guessing what it would look like had a lot more “H-T-H-T-H-T” back and forth sequences. The ones trying to make up the results wound up vastly underestimating variance.”