search for: hofstadl

Dear all, Being a newbie to R, I've trawled through many old posts on this list looking for a solution to my problem, but unfortunately couldn't quite figure it out myself. I'd be very grateful if someone here on this list could perhaps help me out. I have a lattice plot with several panels and would like to add some text next to the y-axis on the right hand side of each row of

Hi there, this is probably simple but I can't seem to figure it out by myself... I have two dataframes (df.1 and df.2): df.1 <- data.frame(year=factor(rep(1:3,3)), level=rep(letters[1:3],3), number=c(11:19)) df.2 <- data.frame(year=factor(c(1:5)), number=c(21:25)) I would like to create a new variable df.1$new, which is supposed to be the sum of each element of df.1$number and those

Hello all, This question concerns the function Dotplot from the Hmisc package. My aim is to compare values between groups in each panel of the Dotplot, with the values of different groups clearly distinguishable by different symbols. All lines and symbols should be coloured in black. Before adding the panel function to the Dotplot, the groups behaved as desired and were marked by different

Hi there, Could someone help me with the following programming problem..? I have written a function that works for my intended purpose, but it is quite closely tied to a particular dataframe and the names of the variables in this dataframe. However, I'd like to use the same function for different dataframes and variables. My problem is that I'm not quite sure how to tell my function in

hi there, I have a list of 5 identical dataframes: mydf <- data.frame(x=c(1:5), y=c(21:25)) mylist <- rep(list(mydf),5) and a factor variable with 5 levels: foo <- c(letters[1:5]) foo <- as.factor(foo) Question: I'd like to add a new variable to each dataframe in the list, each containing only one level of the factor variable. So mylist[[1]] should have a new variable z

Hello there, I have a linear regression model for which I estimated heteroskedasticity-robust (Huber-White) standard errors using the coeftest function in the lmtest-package. Now I would like to inspect the predicted values of the dependent variable for particular groups and include a confidence interval for this prediction. My question: is it possible to estimate confidence intervals for the

hello, the following questions will without doubt reveal some fundamental ignorance, but hopefully you can still help me out. I'd like to bootstrap a coefficient gained on the basis of the coefficients in a logistic regression model (the mean differences in the predicted probabilities between two groups, where each predict() operation uses as the newdata-argument a dataframe of equal size as

Hello! I'm thinking of applying a censored regression model to cross-sectional data, using either the tobit (package survival) or the censReg function (package censReg). The dependent variable is left and right-censored. My hopefully not too silly question is this: I understand that heteroskedasticity and nonnormal errors are even more serious problems in a censored regression than in an

Dear list, My question to follow is not a pure R question but contains also a more general statistical/econometrical part, but I was hoping that perhaps someone knowledgable on this list could offer some help. I have estimated a binary logistic regression model and would like to calculate average marginal effects for certain predictors of interest. The average marginal effect for a continuous