similar to: Inference for R Spam

Hi all, I try to assess the parameters (K1,K2) of a model that describes the adsorption of a molecule onto on adsorbent. equation: dq/dt = K1*C*(qm-q)-K2*q I know the value of 'qm' and I experimentally measure the variables 'q', 'C', and the time 't'. t C q 1 0 144.05047 0.0000000 2 565 99.71492 0.1105625 3 988 74.99426

I can't get the PERL subexpression translated to R. Following, for example, B. Ripley's http://finzi.psych.upenn.edu/R/Rhelp02a/archive/58984.html I am using sub, but it looks like an ugly substitute. Assume I want to extract the first alpha part and the first numeric part, but only if they are in sequence. Do I really have to use the sub twice, first extracting the first variable, then

We have extracted parameters from physiological measurements by fitting SSlogis-like curves with nlsList and nlme. We presented residuals plot in a paper, but a referee argues that these cannot be included (too technical), and r-square values should be given instead to compare the goodness of fit with those of other authors. I remember that 30 years ago in my stat 101, I learned that r-square is

Hi there, I hope I can get advice regarding the calculation of leverage values or studentized residual values of a non-linear regression model. It seems like rstudent() does not work on a nls object. Many thanks in advance! Best regards, Xingli

Dear List, creating factors in a given non-default orders is notoriously difficult to explain in a course. Students love the ifelse construct given below most, but I remember some comment from Martin M?chler (?) that ifelse should be banned from courses. Any better idea? Not necessarily short, easy to remember is important. Dieter data = c(1,7,10,50,70) levs =

I read somewhere that vector graphics such as eps or dpf are more favorable than alternatives (jpeg, bmp or png) for publication because vector graphics scale properly when enlarged. However, my problem is that the file generated from a graph of fixed size is too large (in the order of 10MB) because of many data points in multiple scatterplots. Any suggestions? Thanks, Gang [[alternative HTML

Dear List, assume I want to make a minor local change in a package that is supplied as .rda. For example, I want to get rid of the non-verbose-protected "Iteration" message in GLMM/lme4. Probably I have to load / change / save the package, but could someone help me to get the syntax right? Dieter Menne

Dear R and lme4 users- I am trying to fit a mixed-effects model, with the glmer function in lme4, to right-skewed, zero-inflated, non-normal data representing understory grass and forb biomass (continuous) as a function of tree density (indicated by leaf-area). Thus, I have tried to specify a Gamma distribution with a log-link function but consistently receive an error as follows: >

Thanks to Dieter Menne and Spencer Graves I started to get my way through lsoda() Now I need to use it in with nls() to assess parameters I have a go with a basic example dy/dt = K1*conc I try to assess the value of K1 from a simulated data set with a K1 close to 2. Here is (I think) the best code that I've done so far even though it crashes when I call nls()

Dear friends of lattice, I know how to position trellis plots with print(...,split,more=T) or (...position). Sometimes I wish I had something like the old "par(mfcol=2, mfrow=3)" mechanism, where the next free viewport is automatically chosen. I tried fiddling with grid-viewports, but could not find an easy solution. Did I miss something? Dieter Menne

Is there an easy way to remove data frame columns by name instead of by index? The following gives the idea remove<-c("subj","drug") data[-remove] I found a solution with a few evals and substitutes, similar to that used in reshapeLong, but there must be an easier way out. Dieter --------------------------------------- Dr. Dieter Menne Biomed Software 72074 T?bingen Tel

Dear all, Suppose I have a linear mixed-effects model (from the package nlme) with nested random effects (see below); how would I present the results from the random effects part in a publication? Specifically, I?d like to know: (1) What is the total variance of the random effects at each level? (2) How can I test the significance of the variance components? (3) Is there something like an

In the area plots below, I see 4 triangle ticks at both sides of the bar; I believe these are non-stacked values for p, but they are definitively confusing. In addition, I would like to get the order of the colors in the plot the same as in the legend, and not arranged alphabetically (the factor is ordered, don't touch my order). Hadley once mentioned an undocumented aestetics

Hi Dieter and R community: I tried both of these three versions with ylim as suggested, none work: I am getting only single (pch = 16) not overlayed (pch =3) everytime. *vs 1* require(lattice) xyplot(Sepal.Length ~ Sepal.Width | Species , data= iris, panel= function(x, y, subscripts) { panel.xyplot(x, y, pch=16, col = "green4", ylim = c(0, 10)) panel.lmline(x, y, lty=4, col =

Hi Dieter, Sorry my mistake. I wanted to convert them into Decimal (not Hexadecimal). Given this string, the desired answer follows: > ascii_str <- "ORQ>IK" 79 82 81 62 73 75 > ascii_str2 <- "FDC" 70 68 67 - Gundala Viswanath Jakarta - Indonesia On Mon, Dec 22, 2008 at 5:49 PM, Dieter Menne <dieter.menne at menne-biomed.de> wrote: > Gundala

I am confused by the logic of renaming: # Rename individual list items? Empl<-list(employee="Anna",spouse="Fred") names(Empl)<-c("empl","spo") names(Empl) #[1] "empl" "spo" # worked like a charm... but names(Empl[1])<-"newempl" # no error message, yet .... names(Empl) #[1] "empl" "spo" #

Dear R-Listeners, as the Sweave faq says: http://www.ci.tuwien.ac.at/~leisch/Sweave/FAQ.html creating several figures from one figure chunk does not work, and for standard graphics, a workaround is given. Now I have a multipage trellis plot with an a-priori unknown number of pages, and I don't see an elegant way of dividing it up into multiple pdf-files. I noted there is a "page"

Hi: I need help merging rows. I am trying to merge the 'Month' column using \multirow. For example for the column 'Week' I want July to be merged into one row(weeks 27,28,29,30) and so on for the following weeks. Below, I am creating a PDF using Sweave, MikTex,R-2.8.1 and windows XP to show an example. \documentclass[11pt]{article} \usepackage{longtable,verbatim} \title{How to

Dear List, I am struggling understanding S4 classes. For example, when GLMM summary(glmmML( whatever)) outputs the following line: Estimate Std. Error DF z value Pr(>|z|) (Intercept) 0.856 0.319 45 2.68 0.0073 How do I access the Pr column? Dieter

Dieter Menne wrote: > Hi, Jim, > > there is a typo at the bottom of plotCI: there is an y.to.in which should be > x.to.in. > > See list for an example. > > http://article.gmane.org/gmane.comp.lang.r.general/147103 > > Should be: > nz <- (abs(ui - pmin(x + gap, ui)) * x.to.in) > 0.001 > > Dieter > > Hi Dieter, Thanks for the fix. I have