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 ?


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.

  • 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). $\endgroup$ – Scortchi - Reinstate Monica Apr 21 '15 at 9:46
  • $\begingroup$ Yes @Scortchi! That's why I said most of individual output. $\endgroup$ – Hemant Rupani Apr 21 '15 at 9:49

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.