Re: [R] Need to calculate standard deviation by groups

Hello, Zsuzsa, does ave() with its argument FUN supplied with sd not do what you want? Something like with( Dataset, ave( x = B, C, D, FUN = sd)) should do it. Hth -- Gerrit On Fri, 9 Dec 2011, Zsuzsanna Papp wrote: Hello, please help me with this basic question, I already spent two day

[R] Need to calculate standard deviation by groups

Hello, please help me with this basic question, I already spent two days on the internet and textbooks trying to come up with an answer... I will simplify my question to an example, rather than base it on the original variable names. I have a Dataset with 4 variables, 2 cases. Variable A is a