Significance testing: a picture (well, cartoon) is worth 1000 words.

Statistical significance testing is a pretty tricky concept. We're planning to post an article on it soon, but until we get round to it, here's a link to something excellent on the topic from the xkcd Web comic. They're illustrating exactly what people misunderstand. Maybe we needn't bother with the article after all...

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Comments

Anonymous's picture

Weren't they lucky that exactly 1 of their 20 colour tests gave a result significant at the 5% level?
Anonymous's picture

Almost everyone I've shown this cartoon to is unable to clearly describe why or what it's showing - as far as it goes it's a in joke for people who understand the misunderstanding....
Anonymous's picture

I love xkcd. What does R say? > dbinom(1,20,0.05) [1] 0.3773536 So it happens about 38% of the time if the null is true.