similar to: Backward elimination in regression

Hi everyone I have the following problem: My dataframe has 3 variables: ID, Year and and an outcome variable. The dataframe contains repeated measurements because the subjects filled out a questionnaire every year. The time span covers 2 years. Now I want to check if there is a significant change in the outcome over the 2 years with a paired wilcox.test. The problem: Not every subject

Hi All, I am trying to lable the y-axis on my scatterplot with the following: "Soil moisture content (m3m-3)" I am using the following coding for plotting the graph: plot(soilmoisture~gradientlevel, xlab="Levels of droughting gradient", ylab="Soil moisture content (m3m-3)", bty="l", font.main="2", pch=16, las=1, cex.lab="1.13") I have

Hey all, In order to test if a marker is a risk factor, I built two models (using cox proportional hazard model). One model included this marker, and the other is not. Then, I use R package risksetROC to test how much predictive value did the marker add to this model. I get two C statistics by analyzing the linear predictors of the two models into this package. The qustion is How to test if two

I noticed that the text() command adds text to a plot. Is there a way to either make the plot blank or add text to a "blank sheet". I would like to "plot" a page that contains just text, no plot lines, labels, etc. Suggestions? Kevin [[alternative HTML version deleted]]

Hello! I would like to do some tables for several variables and I would like to write a loop that does the table for each variable. I should also point out that my data set has several missing observations and sometimes the observations that are missing are not the same for all my variables. What I would like to do: table(StoreData$CompanyID, !is.na(StoreData$P2))

Hi, i want to construct a data set similar to "AirPassengers". Its attributes are following. > attributes(AirPassengers) $tsp [1] 1949.000 1960.917 12.000 $class [1] "ts" How Can I construct a data set similar to it having same class and attributes. Thanks -- Amar Kumar Nandan ?:nandan.amar at gmail.com http://aknandan.co.nr

Dear List members, I really, like the feature that one can call R functions with mathematical expressions, e.g. curve(x^2, 0, 1) I wonder, how I can construct in a simple way a function like mycurve = function (expr) {...} such that that a call mycurve(x^2) has the same effect as the call curve(x^2, -100,100) Below is some code that works, but it seems much to complicated: it first

I wish place the following axis label in such a manner that some of the text is plain and the scientific name is in italics (i.e. a mixture of two font types) Using plot: mtext("Total Landings of Pecten maximus (tonnes)",font,=3, side=2, line=3) makes everything italic, but how do I apply the font change to only "Pecten maximus"? Rgds Phil

Say I have a list of variables,  listVar <- list(age,sex) I am looking for a way to either 1- create a vector c("age","sex") from it, or 2- get the names one by one in a for loop such as these     a)  for (i in 1:length(listVar)) rownames(result)[i] <- ???     b)  for(i in listVar) print (variable's name) Any help much appreciated. [[alternative HTML version

Is there a way to convince R to create a character vector without using the quotes? This works ex1 <- c("first","second") but when I try this it doesn't ext <- as.character(c(first,second)) it complains. I have many variables to put into character vectors so dispensing with the quotes would be useful. Thanks Jim =============================== Dr. Jim Maas

Hi all, I would like to replace the for loop in the code below with a function to improve the speed and to make the script more efficient. The loop creates a vector of integers (x) with the probability of f for each integer. The length of f is variable, but sums to 1. I tried to use a function with optional arguments which did not work. Here is the code: f <- data.matrix(c(0.5,0.15,0.35))

Hello I have a time-comsuming program which need to simplify, I have tested the annotated program as follow: > #define function which will be call > calsta <- function(c, n=100000) + { + i <- seq(from=0, length=c) + logx <- lchoose(NT-n, CT-i) + lchoose(n, i) + logmax <- max(logx) + logmax + log(sum(exp(logx - logmax))) + } > CT=6000 #assignment to CT >

Hi all, I have two vectors (columns) called "efinal" and "efinal 2". I want to plot them on the same plot and "draw" a shaded area beween the two lines using function polygon I have tried all but I don ?t understand the polygon area, can you help me with examples? plot(efinal,type="l",ylim=range(min(efinal2),

? stato filtrato un testo allegato il cui set di caratteri non era indicato... Nome: non disponibile URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20130423/641d9950/attachment.pl>

hi, I'd like to do graphs like shown on the right panel on the following link: http://www.clinchem.org/cgi/content/full/53/8/1544/F1 (if link doesn't work see attached file) Any help and ideas highly appreciated, thanks in advance. Thomas von K?nel Human Genetics Uni Berne

Dear all I am new R user, and trying to learn more. I am doing linear regression analysis in R with my data. I am trying to find the way to calculate the slope value (coefficient of x) to degree of slope. Please give me idea on this. Thanking you in anticipation Warm regardMS _________________________________________________________________ [[alternative HTML version

Dear expeRts, I it possible to have serif labels in the following plot? x <- 1:10 y <- x plot(x, y, type="b", xlab=expression(x[1]), ylab=expression(x[2])) I know that one can use pdf(, family="serif"), but then also the axis tick marks are printed in serif font. Apart from the fact that it may not look nice, I'm just interested if one can have serif axis labels

Did anyone know whether the problem " it doesn't evaluate \Sexpr{} in Sweave" has been fixed? I checked r help page and realized it was asked a couple of years ago. But I didn't find solutions. Thanks for your help in advance! Hua [[alternative HTML version deleted]]

Hello, This is very basic and very frustrating. Suppose this: >A=5 >B=5 >C=10 > ls() "A" "B" "C" I would like this >xpto() 5 5 10 How can I do xpto()? Thanks Rui [[alternative HTML version deleted]]

I would like to split a string into words at its blanks but also to preserve all blanks. Example: c(" some words to split ") should become c(" ", "some", " ", " words", " ", "to" , " ", "split", " ") I was not able to achieve this via strsplit() . But I am not familiar with regular