In a previous article I looked at how to go wrong with the mean. Today, I will look at a set of alternative measures that deal with some problems of the mean; in particular, they deal well with data that is highly skewed or has outliers. This set is the trimmed mean, the most well known of which is the median.

What is the mean?

The average, or mean, or, more formally, the arithmetic mean, is one of the simplest statistics there is. You have a bunch of numbers, you add them up, divide by how many there are, and …. That’s it! How could you go wrong with the mean? Well …. It’s surprisingly easy to do so.First, a good example, to set the stage. If you weigh 5 people (Peter, John, Mary, Ed and Sally) and they weigh 180, 190, 130, 186 and 100 pounds, you can just add that up, divide by 5 and you’ve got the average weight for those 5 people. That’s the mean. Read more!