[R] nlme::lme sigma parameter standard deviation or variance?

[Courtney Van Den elzen]

Hi R-help,

I am a researcher fitting linear mixed models using the package nlme. I am
wondering whether the sigma value that is outputted as part of the model
object is standard deviation or variance? for example, I might fit a model

lme_mod <- nlme::lme(response ~ predictor1 + predictor2, random =
(~1|grouping1))

I am wondering whether lme_mod$sigma is actually a standard deviation or if
it's a variance.

Thanks so much,
Courtney

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