similar to: dnorm() lead to a probability >1

Howdee, My question appears at #6 below: 1. I want to model the growth of each of a large number of individuals using a 4-parameter logistic growth curve. 2. nlme does not converge with the random structure that I want to use. 3. nlsList does not converge for some individuals. 4. I decided to go around nlsList using: t(sapply(split(data, list(data$id)), function(subd){coef(nls(mass ~

Howdee, *** I know that the lmList() function exists, yet I don't want to use it. *** Would anyone be kind enough to tell how I can apply the function lm() to each level of a given factor so to obtain the intercept and slope for each factor level within a matrix? For instance, suppose a dataframe containing 3 variables: id, x and y. I want to compute the function lm() for each level

Is there a way to apply a function, say cor(), to each combination of some number of variables, and this, without using loops? For example, I have day, hour, var1 and var2. How could I compute cor(var1,var2) for each day*hour combination and obtain a matrix with day, hour and the cor value for each combination? Thanks for your time, Marc =================== Marc Bélisle Professeur adjoint

Howdee, I am able to fit a 4-parameter logistic growth curve to a dataset which comprise many individuals (using R v. 2.3.1). Yet, if I want to obtain the parameters for each individual (i.e., for each 'id') using nlsList, then I obtain an Error message which I have trouble interpreting. Any advice as to how I can solve this problem? Thanks for your time, Marc > reg <-nls(mass ~

Hi there, I have 3 numeric variables: day (e.g., 05), month (e.g., 06), year (e.g., 2009). I would like to create a (string) variable of the following form: month/day/year (e.g., 06/05/2009). I would be grateful to anyone who could point me toward a solution. Sincerely, Marc =================== Marc B?lisle Professeur agr?g? Chaire de recherche du Canada en ?cologie spatiale et en ?cologie

How do one dertermine the optimal number of rescaling cycles to use when performing DCA using the decorana function (library vegan)? Thanks for your time, Marc =================== Marc Bélisle Professeur adjoint Chaire de recherche du Canada en écologie spatiale et en écologie du paysage Département de biologie Université de Sherbrooke 2500 Boul. de l'Université Sherbrooke, Québec J1K 2R1

I can't seem to be able to change the font size in an effect display. I've tried the following: > par(cex.lab=4) > plot(effect ("alti",reg8), ylab="detection probability") and > plot(effect ("alti",reg8), ylab="detection probability", cex=4) but nothing changes. Can anyone help me? thanks. Emilie Berthiaume graduate student

Hi All, Why would calls to dnorm and dmvnorm return values that are above 1? For example, > dnorm(0.00003,mean=0, sd=0.1) [1] 3.989423 This is happening on two different installations of R that I have. Thank you. Hailu [[alternative HTML version deleted]]

Hi there, I'm new to R and despite searching today, I can't find a function which will compute the adjoint of a matrix A. Does this adjoint function exist in R? Thanks in advance!

Hi, I'm just getting started with R and I'm having problems with some simple operations: I want to get the the sum of the column "SStot" for each year using the function by. The data set is named "SS". I've tried this: by (SS, year, sum(SStot)) and it's not working. Is it because there's a different number of rows for each year? How else can I do

Hi list! I did the following regression: reg1 <- glm(alti~sp + ovent + vivent + nuage, family=gaussian, data=meteo1) I was interested in knowing the effect of the species (sp) in reg1 and so I used the function «effect»: effect.sp <- effect ("sp", reg1, se=TRUE) with this output: sp AK BW NH OS RT SS 2.730101 2.885363 2.753774 2.750311

How do you calculate the percentage of data within 2SD, 3SD, 4SD, 5SD, and 6SD of the mean? I used the following link as the data I'm working with: nb10 <- read.table("http://www.adjoint-functors.net/su/web/314/R/NB10") if this helps answer my question. Can you please explain how to calculate the SD's? Please be specific in which part of the function changes when

Okay, so I have a homework projecr for R, and we had to input the following link as some sort of data: nb10 <- read.table("http://www.adjoint-functors.net/su/web/314/R/NB10"). Afterwards, we have to use fivenum(nb10) to find max, min, quantiles, and sd, but I'm okay with this. The next question is where I'm stuck. The question is as follows; Compare the median (use the

Dear all, I am trying to avoid the warnings produced by: > x <- -2:2 > log(x) [1] NaN NaN -Inf 0.0000000 0.6931472 Warning message: production de NaN in: log(x) I thought that using ifelse would be a solution, but it is not the case: > ifelse(test = x < 0, yes = NaN, no = log(x)) [1] NaN NaN -Inf 0.0000000 0.6931472 Warning message: production

thanks a lot Renaud. but i was interested in Finney's fiducial confidence intervals of LD50 so to obtain comparable results with SPSS. But your reply leads me to the next question: does anybody know what is the best method (asymptotic, bootstrap etc.) for calculating confidence intervals of LD50? i could "get rid" of Finney's fiducial confidence intervals but

Hello, I am beginning with R and I would like to test a non linear model. But I do not find exactly wath I am looking for in nls packages (or I do not know where to search). I would like to try a model like this : y=b * x exp(n)/(a exp(n) + x exp (n)) Where a = a0 + a1z b= b0 + b1z x and z are variables y the variable that I am trying to modelise a0, a1, b0 and b1 are parameters to determine. I

Hi list, is there any direct way to obtain confidence intervals for the regression slope from lm, predict.lm or the like? (If not, is there any reason? This is also missing in some other statistics softwares, and I thought this would be quite a standard application.) I know that it's easy to implement but it's for explanation to people who faint if they have to do their own programming...

Hello, Is there an accepted way to convey, for regression trees, something akin to R-squared? I'm developing regression trees for a continuous y variable and I'd like to say how well they are doing. In particular, I'm analyzing the results of a simulation model having highly non-linear behavior, and asking what characteristics of the inputs are related to a particular

Hi, can anyone help me with this problem i''ve got! I have a problem with routing on my Mandrake 7.2 Linux Box i was wondering if you could help me with. I live in Australia and as broadband access isn''t very available at the moment, i have 2 modems to dialup to my isp (dynamic ips assigned) to increase my bandwidth at an affordable level. What currently happens is i have a

Dear R-users, I am a novice R-user with some experience in using the RMS package for taking nomograms after various survival models. This time, I am trying to plot a nomogram after a Random Effects Cox, implemented by the "coxme" package. My questions are: 1. Is it possible to take a nomogram directly after the coxme survival function? 2. If not is there a way to take the linear