The assorted finds of Artefact Publishing

Statistics pet peeve

In the last few years I must have read the following statement (more or less) at least half a dozen times: “half the population has less than 100 IQ, because 100 is the average IQ of the population.” And every single time I am tempted to post a reply setting the person who wrote it right. I haven’t yet, but one day I just know I’ll flip out and do it.

Is it so hard to understand what an average is? That maybe everyone has 100 IQ, or that 90% of people have a 90 IQ and that the other 10% have an IQ which is much greater than 100? Gah.

Funny the little things that incommensurately irk one, isn’t it?

Posted by jamie on October 21, 2003 18:09+13:00


Just in case someone is thinking of saying that IQ scores form a normal distribution, so that 50% of people have above/below average IQ, let me say these things:

Posted by: Jamie on October 21, 2003 19:52+13:00

Which reminds me of that line "You know how dumb the average person is? Well, half of them are even dumber than that!"

Posted by: Shaun on October 22, 2003 08:51+13:00

I have a greater than average number of legs.

Posted by: stephen on October 22, 2003 09:14+13:00

People who use the word “average” at all are already pushing it. They should use “mean” or “median” and then it becomes clear what they mean. As it is, people use “average” to mean both. (Though they use “average” for “mean” more often, they are after the sense of “median”.)

So if you wanted to be charitable about these people you encounter, just pretend that they are saying “median” and all will be well.

Posted by: michael on October 23, 2003 12:26+13:00

That would be charitable indeed, but then I’d feel compelled to pull them up for tautology!

Posted by: Jamie on October 23, 2003 13:25+13:00

Lads, there is no necessary correlation between the technical usage of words, and their popular meaning, or between the knowledge of scholars and what everyone knows.

Posted by: stephen on October 24, 2003 09:28+13:00