Thank you for your help! It works beautifully, but how would I transpose the results?
What I am getting is indeed: 7200 23955 34563 8934 16.39977 10.03896 11.234 14.02 I'd like the final output to be: subject_id hr_Stand_Deviation 7200 16.39977 23955 10.03896 34563 11.234 8934 14.02 What I have realized so far is: tapply() is outputting an array, so I need to transpose the array. Then I read that you need to use aperm to transpose an array, but I don' t know what permutation vector I should choose Then even if it is transposed, I'd like to retitle the columns to be 'subject_id' and 'hr_standard_deviation' I tried to convert the array to a table and then to a matrix, but I'm not sure what the best way to go is from this point. Thanks again! On Thu, Nov 20, 2008 at 12:17 AM, Simon Blomberg <[EMAIL PROTECTED]>wrote: > How about: > > with(dat, tapply(HR, SUBJECT_ID, sd)) > > Assuming your data frame is named dat. > > On Wed, 2008-11-19 at 23:59 -0500, pufftissue pufftissue wrote: > > *Hi all, > > > > I know this is probably basic, but I have proven to be a slow learner in > any > > programming language. Anyhow, > > how can I calculate the SD for each person in my table? I have two > patients > > in this R data.frame, 7200 and 23955. > > I extracted this from a relational database, but am I better off > attempting > > to compute SD in SQL, or is this easily accomplished in R? > > > > > > * SUBJECT_ID HR > > 1 7200 158 > > 2 7200 165 > > 3 7200 138 > > 4 7200 152 > > 5 7200 139 > > 6 7200 157 > > 7 7200 186 > > 8 23955 167 > > 9 23955 162 > > 10 23955 171 > > 11 23955 139 > > 12 23955 170 > > 13 23955 177 > > 14 23955 180 > > 15 23955 176 > > 16 23955 172 > > 17 23955 179 > > 18 23955 181 > > 19 23955 169 > > 20 23955 168 > > 21 23955 185 > > 22 23955 181 > > 23 23955 191 > > 24 23955 179 > > 25 23955 178 > > 26 23955 184 > > 27 23955 179 > > 28 23955 172 > > 29 23955 173 > > 30 23955 182 > > 31 23955 174 > > > > * > > So, what I would want is a table of 800 patients with a SD for their > heart > > rates: > > > > subject id Heart Rate SD > > > > 7200 20 (for example) > > 23955 18 (for example)* > > > > Thank you! > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-help@r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > > and provide commented, minimal, self-contained, reproducible code. > -- > Simon Blomberg, BSc (Hons), PhD, MAppStat. > Lecturer and Consultant Statistician > Faculty of Biological and Chemical Sciences > The University of Queensland > St. Lucia Queensland 4072 > Australia > Room 320 Goddard Building (8) > T: +61 7 3365 2506 > http://www.uq.edu.au/~uqsblomb <http://www.uq.edu.au/%7Euqsblomb> > email: S.Blomberg1_at_uq.edu.au > > Policies: > 1. I will NOT analyse your data for you. > 2. Your deadline is your problem. > > The combination of some data and an aching desire for > an answer does not ensure that a reasonable answer can > be extracted from a given body of data. - John Tukey. > > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
