Wednesday, February 27, 2013

Median Versus Average

Median is not average. In fact, given typical power law distributions such as long tails the median is often lower than average.

Given a set of one mile race times: 4:14, 4:35, 4:41, 4:44, 4:49, 4:53, 4:58

The average is the sum of those times. If they are added together you get 1974 seconds. The average is 4:42.

The median is the middle time. The guy who has 50% ahead of him and 50% behind him. In this case that is 4:44.

In other words, being the "average" or "above average" at something, like running, income or drinking alcohol, often means much more than the median.


  1. Oftentimes you insult the intelligence of your readers ...

  2. Perhaps, but at least one seven year old has read my blog. Plus a number of college kids that aren't science and engineering majors read it from time to time.