Thinking like a scientist

Nearly every day, newspapers report on new scientific breakthroughs.  Scientists provide measures of their uncertainty in the results, expressed as a p-value.

The p-value is a statistical measure of the randomness of the results; a lower p-value indicates that the reported result is not likely due to chance.  In scientific studies, a p-value of 0.05 (or 5% likelihood of the result being due to random chance) is considered significant. Put another way, if the same test were done 100 times, a result would have to happen 95 times out of 100 to be considered significant.

"'So we did the study again, and got no link. It was probably a--' RESEARCH CONFLICTED ON GREEN JELLY BEAN/ACNE LINK; MORE STUDY RECOMMENDED!"

http://www.xkcd.com/882

Scientists test their hypotheses multiple times to be sure of the significance of their results.  Even though one test may reach a significant p-value, there’s still that 5% chance that it could be due to chance.

Unfortunately, that doesn’t make for good newspaper headlines.  So, when you read news about science, think like a scientist and look at the data and results with a scientifically-critical eye.

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