The top fallacy in statistics: sample size

Thursday, October 7th, 2010

In my foolishness, I signed up for a ten-week module on statistics whilst studying for my Maths degree. And I hated it with a vengeance. It soon became crystal clear that I found 99 out of 100 topics exceptionally dull.

However, with the spiralling number of surveys appearing in the media with each passing year, having a certain amount of knowledge about statistics has come to my aid on numerous occasions. Because it turns out that even intelligent people don’t really understand statistics at all.

Here, I’d simply like to address the number one, burning misunderstanding people have about statistics: the sample size has to be similar in number to the total population in a study.

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Stretching the truth by snipping the figures

Wednesday, April 15th, 2009

Here’s something that winds me up. This is a graph that was published to accompany a high-profile hardware launch last year. I won’t name names, but you can probably guess who produced it and what they were trying to show:

As you can see, across various tests the red bar is three, four, even six times as tall as the green one. But hold on — because that’s not an accurate reflection of relative performance. (more…)