Reader Comments

Post a new comment on this article

Statistical notation

Posted by JohnMashey on 20 Aug 2015 at 21:16 GMT

"edited on average (geometric mean ±SD) 1.9±2.7 times"

What do people think that means? See:

https://en.wikipedia.org/...
https://en.wikipedia.org/...
https://en.wikipedia.org/...

I'd suggest that the text just specific GM's and the table give GSDs, but with out the ± notation. Without computing skew and kurtosis of the log distribution, we don't really know much of its shape.

No competing interests declared.

RE: Statistical notation

WilsonAdam replied to JohnMashey on 21 Aug 2015 at 01:26 GMT

Thanks John,

All the SDs that go with geometric means are geometric SDs. I thought it would be redundant to write ("geometric mean and geometric sd"), but perhaps it would have been clearer to be explicit. Regarding the +/- nomenclature, of course a geometric mean is actually multiplicative, not additive. We could have used */, but that could have also been confusing, especially for anyone not familiar with geometric SDs.

Competing interests declared: Author of article