Re: [R] aggregate similar to SPSS

2007-04-25 Thread Tim Churches
Andrew Robinson [EMAIL PROTECTED] wrote: can I suggest, without offending, that you purchase and read Peter Dalgaard's Introductory Statistics with R or Michael Crawley's Statistics: An Introduction using R or Venables and Ripley's Modern Applied Statistics with S or Maindonald and Braun's

Re: [R] Sum of specific column

2007-04-25 Thread Stephen Weigand
On 4/25/07, Spilak,Jacqueline [Edm] [EMAIL PROTECTED] wrote: I have a data set that I have imported (not sure if that makes a difference) and I would like to calculate the sum of only specific columns. I have tried colSums(dataset, by=list(dataset$col5), dims=1) and I get an error of unused

Re: [R] ANOVA results in R conflicting with results in other software packages

2007-04-25 Thread Richard M. Heiberger
It looks from your tables that you have the same residual in both programs, suggesting that the arithmetic is correct. The terms are in a different order. Since anova() gives sequential sums of squares (Type I), the numerical values depend on the order. Force both programs to use the same order

Re: [R] ANOVA results in R conflicting with results in other software packages

2007-04-25 Thread Simon Blomberg
R uses treatment contrasts for factors (ie 0/1 coding) by default. Systat is using sum (ie sum to zero) contrasts: Try this: options(contrasts=c(contr.sum, contr.poly) lm(maladapt~host*increase*size2)-fm Anova(fm, type=III) I won't discuss the dangers of types of sums of squares and different

[R] Reduced Error Logistic Regression, and R?

2007-04-25 Thread Tim Churches
This news item in a data mining newsletter makes various claims for a technique called Reduced Error Logistic Regression: http://www.kdnuggets.com/news/2007/n08/12i.html In brief, are these (ambitious) claims justified and if so, has this technique been implemented in R (or does anyone have

Re: [R] regular expressions with grep() and negative indexing

2007-04-25 Thread Stephen Tucker
Thanks guys for the suggestions guys- I come across this problem a lot but now I have many solutions. Thank you, Stephen --- Peter Dalgaard [EMAIL PROTECTED] wrote: Peter Dalgaard wrote: Stephen Tucker wrote: Dear R-helpers, Does anyone know how to use regular expressions to

Re: [R] Reduced Error Logistic Regression, and R?

2007-04-25 Thread Roy Mendelssohn
I don't know about the claims, but I do know about this: Recent News: January 31, 2007. St. Louis, MO - Rice Analytics applied for a U.S. patent this week on a generalized form of Reduced Error Logistic Regression. This generalized form allows repeated measures, multilevel, and

Re: [R] levelplot and unequal cell sizes

2007-04-25 Thread Waichler, Scott R
You are right, panel.levelplot is indeed assuming that the boundaries are between consecutive midpoints. There is no built in way around that; there simply isn't enough information available to the panel function. The cleanest solution, in principle, is to write your own panel function

Re: [R] How to identify and exclude the outliers with R?

2007-04-25 Thread Shao
Thanks. I think the package outliers is what I need. Shao chunxuan On 4/25/07, Horace Tso [EMAIL PROTECTED] wrote: It depends on the nature of your data set. There is a package simply called 'outliers', which has the Grubbs/Dixon/Cochran tests. There is also the Bonferroni outlier test in

[R] gnls warning message

2007-04-25 Thread Pedro Mardones
Dear R users; I was trying to fit a nonlinear model using gnls (nlme version 3.1-80, R 2.5.0, WinXP) and I got the following error and warning message: Error in gnls(ht ~ a1 * hd * (1 - a2 * exp(-a3 * (dbh/dq2))), data = hdat, : Step halving factor reduced below minimum in NLS step In

Re: [R] Reduced Error Logistic Regression, and R?

2007-04-25 Thread Simon Blomberg
From what I've read (which isn't much), the idea is to estimate a utility (preference) function for discrete categories, using logistic regression, under the assumption that the residuals of the linear predictor of the utilities are ~ Type I Gumbel. This implies the independence of irrelevant

Re: [R] R News, volume 7, issue 1 is now available --error in AMMI article

2007-04-25 Thread Lux Zhang
Hi, In this newsletter (Vol 7, 1),the article on AMMI by Onofri and Ciriofolo presented a AMMI function. One of arguments for this function AMMI (Page 17) is biplot. There is a biplot fucntion from {stats} package. I guess they are not the same. Could the authors clarify that? Thanks,

Re: [R] gnls warning message

2007-04-25 Thread Prof Brian Ripley
From the help page: control: a list of control values ... Now, control=c(minFactor=1/2048) is not a list but a numeric vector. So it is warning you about incorrect usage. On Thu, 26 Apr 2007, Pedro Mardones wrote: Dear R users; I was trying to fit a nonlinear model using gnls (nlme version

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