5 October 2015

Summarising with Box and Whisker plots

In the Northern Hemisphere, it is the start of the school year, and thousands of eager students are beginning their study of statistics. I know this because this is the time of year when lots of people watch my video, Types of Data. On 23rd August the hits on the video bounced up out of their holiday slumber, just as they do every year. They gradually dwindle away until the end of January when they have a second jump in popularity, I suspect at the start of the second semester. One of the first topics in many statistics courses is summary […]
29 April 2013

The median outclasses the mean

The median suffers from poor marketing. All my time at school the “average” was always calculated as the arithmetic mean, by adding up all the scores and then dividing by the number of scores. When we were taught about the median, it seemed like an inferior version of the mean. It was the thing you worked out when you weren’t smart enough to add and divide. It was used for house prices, and that was about it. Of course the mean was the superior product! Why wouldn’t you use the mean? I’ve been preparing resources for teaching the fabulous new […]
3 January 2012

The meaning of the mean

Here is an exercise you might like to try on a class or individual, when introducing the mean. I have found it interesting and enlightening for all parties, especially those who think they know everything. Dr Nic: Tell me what a mean is, as if explaining it to someone who doesn’t know about statistics. Student: It’s an average. Dr Nic: Correct, however you haven’t really increased my understanding with that description. Student: It is what you get when you add all the numbers together and divide by the number of numbers. Dr Nic: That is a correct description of how to calculate a mean. Still […]