How many significant digits?

Just because your statistical package spits out values that look like this: 0.243444128999 or 984112.6868688670 or even a modest 23.3421 does not mean that they have a place in your life, your paper, or even your analysis. Round them off at a reasonable level so the significance of the digits matches reality.

Back when I was a student and we used slide rules (really!), this was one of the first things we learned. Rounding is your friend. Maybe not if your project is to discover the Higgs-Boson, but if you are trying to tell us about just about anything else, round to something reasonable.

The larger lesson is that your data and your analyses should make sense. You should make them clear and careful. Pay attention to significant digits. Pay attention to degrees of freedom. Before you just put the analysis that your program spat out into you paper, think a minute. Does it make any sense?

Clarity is your friend, in analyses, in writing, in experimental design.

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About Joan E. Strassmann

Evolutionary biologist, studies social behavior in insects & microbes, interested in education, travel, birds, tropics, nature, food; biology professor at Washington University in St. Louis
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