I have represented standard deviation as "±SD" before in publications. But I like to have opinions on this. Is it appropriate to use the notation '±' with SD ? Or is it only for Standard error ?
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3$\begingroup$ The the second bullet point of the wiki page for the plus minus operator already answers your question. $\endgroup$– user603Apr 21, 2015 at 9:20
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Yes! you can represent standard deviation as "±SD".
For Example:- $\bar x\pm 2\times SD$, it just shows the lower and upper limit for most of individual output $x_i$ of Normal data. ($\mu ~rather~than~ \bar x$)
and, $\bar x\pm 2\times SE~of~mean$, shows lower and upper limit of population mean.
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2$\begingroup$ $\bar{x} \pm 2\mathrm{SD}$ could be an asymptotic 95% prediction interval for a Gaussian random variable (asymptotic because the sample mean, & perhaps the standard deviation, are estimated from the data; so exact prediction intervals are somewhat wider). $\endgroup$ Apr 21, 2015 at 9:46
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$\begingroup$ Yes @Scortchi! That's why I said most of individual output. $\endgroup$ Apr 21, 2015 at 9:49
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