similar to: R algorithm for maximum curvatures measures of nonlinear models

Dear colleagues, Von Bertalanffy model is commonly adjust to data on fish length (TL) and age (AGE) TL= Linf*(1-exp(-K*(AGE-t0)). Linf, K and t0 are parameters of the model. One main goal of the growth study is the comparison of growth parameter estimates between sexes of the same species, or estimates from different populations. The realibility statistical tests normally applied are highly

I'm not sure I'm barking up the right tree here, but would I need to make use of groups to plot two separate datasets within ONE panel in xyplot? The desired end result is a single xy plot of two separate (but similar in values and ranges). Full code follows, xyplot code at bottom #########Determine Frequencies ##########coastal_slope #needs the maptools package to read ESRI grid

Hi all; I'm trying to fit a reparameterization of the assymptotic regression model as that shown in Ratkowsky (1990) page 96. Y~y1+(((y2-y1)*(1-((y2-y3)/(y3-y1))^(2*(X-x1)/(x2-x1))))/(1-((y2-y3)/(y3-y1))^2)) where y1,y2,y3 are expected-values for X=x1, X=x2, and X=average(x1,x2), respectively. I tried first with Statistica v7 by LS and Gauss-Newton algorithm without success (no

Aloha all, I know too little about what I'm about to write and hope I'm not wasting your time. For a class I'm teaching in archaeological data analysis, I'm trying to put together a routine that calculates the so-called Petersen index and, especially, confidence intervals for the index. This was introduced to archaeologists by N.R.J. Fieller and A. Turner in an article

Hi It is preferable to echo your posts to r-help, you usually get more answers and some definitelly superb to mine. It is also better to start a new mail if your question has nothing to do with original subject "Maura E Monville" <maura.monville at gmail.com> napsal dne 01.10.2007 17:44:43: > Unluckily I do not have the privilege of practising with R all day > long. I

Hi all, I'm adjusting a nonlinear regression model for data that has a categorigal variable present. So, I can use nls() to do this considering the categorical variable, like this #------------------------------------------------------------ da <- expand.grid(tr=gl(2,1,la=c("tr")), x=1:12) da$y <- 10*da$x/(3+da$x)+rnorm(da$x,0,0.1) plot(y~x, da) n0 <-

Dear All,i applied "NbClust", to my data to find optimum number of clusters, and got following resultsNow, i don't know how to read these results. more precisely, i would like to know, how to see which method is more precise for my data considering these index values.your help is needed...thanks in advance Eliza Botto > dput(Eliza)structure(list(All.index = structure(c(2, 3, 4, 5,

Dear R-users, I'd appreciate your statistical opinion on the following problem. I'm fitting the four parameter logistic model [f(x) = a + (b - a)/(1 + exp((c - x)*d))] to assay data. We have a lot of samples to fit and my aim is to classify these samples into following groups: 1. no interrelation all results about =~ 0 too low concentration 2. only full

Actually, I re-read the post and think it needs clarification. We may both be right. If the question is "I am building a model and want to know if I should retain this random effect?" (or something like that) then the LRT should be used to compare the fitted model against another model. This would be accomplished via anova(). In other multilevel programs, the variance components are

I have a function in R^2, say f <- function(x,y) { ...skipped } I want to plot this function using contour, persp. wireframe, etc. I know that the function has a global minimum at (x0, y0) The naive approach is to evaluate the function on the outer product of two arrays, like this: sx <- c(seq(-3, x0, len = 100), seq(x0, 3, len = 100)[-1]) sy <- c(seq(-3, y0, len = 100), seq(y0, 3,

I used the wrong address. This was meant as a reply to another post. On 10/17/07 10:55, thomas.schwander at mvv.de wrote: > Hi Jonathan, > > I read your post in the R-Help. Did you get rid off the problem? I'm standing inf > ront of the same problem... If you've got an answer to me to drae a curly bracket, > could you please be so kind to tell me who you did? I missed

Hi! I'm learning mgcv, and reading Simon Wood's book on GAMs, as recommended to me earlier by some folks on this list. I've run into a question to which I can't find the answer in his book, so I'm hoping somebody here knows. My outcome variable is binary, so I'm doing a binomial fit with gam(). I have five independent variables, all continuous, all uniformly

GENERAL REFERENCE ON NONLINEAR OPTIMIZATION? What are your favorite references on nonlinear optimization? I like Bates and Watts (1988) Nonlinear Regression Analysis and Its Applications (Wiley), especially for its key insights regarding parameter effects vs. intrinsic curvature. Before I spent time and money on several of the refences cited on the help pages for "optim",

Hello R users, I'm analyzing an experiment in a balanced incomplet block design (BIB). The effect of blocks are assumed to be random, so I'm using nlme::lme for this. I'm analysing another more complex experiments and I notice some diferences from doBy::popMeans() compared multcomp::glht() and contrast::contrast(). In my example, glht() and contrast() were equal I suspect popMeans()

Hello list, I'm doing a table with scores and I want include colors to represent status of an individual. I'm using sweave <<results=tex>>= and xtable but I can't get a result I want. My attemps are #----------------------------------------------------------------------------- # code R da <- data.frame(id=letters[1:5], score=1:5*2) col <- function(x){

Dear , Dovecot List ( Everyone ) I have some problem about dovecot/postfix/mysql Would u like to tell me about the solution ? sir Thank you very much for advance. Sir Best Regards, Pratchaya ================================== ================================== ================================== This is my problem/error sir 1. ERROR = "" A NO

Hello list, I have plots with long strings in main=, ylab= or xlab=. So, in I my script I use break long lines to avoid lines hiden on my monitor and in sweave document pages. I use graphics like this plot(1, main="aaaaaaaaaaaaaaaaaaaa bbbbbbbbbbbbbbbbbbbb") but I would like a plot result like this plot(1, main="aaaaaaaaaaaaaaaaaaaa bbbbbbbbbbbbbbbbbbbb") I

Hi, I've data from an incomplete fatorial design. One level of a factor doesn't has the levels of the other. When I use lm(), the summary() return NA for that non estimable parameters. Ok, I understant it. But I use contrast::contrast(), gmodels::estimable(), multcomp::glht() and all these fail when model has NA estimates. This is becouse vcov() and coef() has different dimensions. Is

Colin, If your propose is to create a ternary plot with points and vectors, I think easier do this with graphics based plots instead of trellis based plots. Although, with little work you can do with trellis too. I gave you a reproducible code to put an arrow in a ternary plot. I use the function locator() to extract coordinates. The code is the following

Hi R users, I sent a message yesterday about NA in model estimates ( http://r.789695.n4.nabble.com/How-set-lm-to-don-t-return-NA-in-summary-td3722587.html). If I use aov() instead of lm() I get no NA in model estimates and I use gmodels::estimable() without problems. Ok! Now I'm performing a lot of contrasts and I need correcting for multiplicity. So, I can use multcomp::glht() for this.