Hi R-Experts,
I have a vector of length 72. I want to break it into 12 parts and want to take
standerd deviation of each group. Please help me in this regard.
Thanks,
Sumanta.
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sumanta basak wrote:
Hi R-Experts,
I have a vector of length 72. I want to break it into 12 parts and want to
take standerd deviation of each group. Please help me in this regard.
x - 1:72
apply(matrix(x, ncol=12), 2, sd)
Uwe Ligges
Thanks,
Sumanta.
Try this:
tapply(x, cut(x, 12), sd)
On 4/28/06, sumanta basak [EMAIL PROTECTED] wrote:
Hi R-Experts,
I have a vector of length 72. I want to break it into 12 parts and want to
take standerd deviation of each group. Please help me in this regard.
Thanks,
Sumanta.
You didn't say _how_ you want the vector to be broken up,
so you get two different answers from Uwe and Gabor. Uwe's
answer group every six elements into one group, in the order
they appear in the vector (which, BTW, can be simplified to
just sd(matrix(x, ncol=12)). Gabor's answer put the
Good point.
Following Andy's comment sd(matrix(sort(x), nc=12))
could also be used if you want them broken up
by 6 smallest, next 6 smallest, etc. although
there might be differences in the case of ties.
Using tapply here are a number of ways of breaking
it up (the first three give the same
