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Dear R-helpers, I have found a slightly annoying problem when trying to plot lines on graphs. I first created my data using tapply, thus:- y1=as.vector(fit1$coef$random$id) x1=tapply(o1,id,median,na.rm=T...

I am trying to analyse recurrent failure times using survfitr from the survrec package. To do this, I need to "Create a survival recurrent object" using Survr. But, when I do this, I get an error "Error in Survr(r1d...

Dear Helpers, I wrote a simple function to standardise variables if they contain more than one value. If the elements of the variable are all identical, then I want the function to return zero. When I submit variables whose elements...

Dear R-helpers, I have just installed R2.0.0 onto my machine which already had R1.9.1 present. I then tried to add to R2.0.0 a library called GLMM written by James McBroom for R1.6...

Dear R-helpers, I want to try to extract residuals from a multi-level linear mixed effects model, to correlate with another variable. I need to know which residuals relate to which experimental units in the lme. I can show...

Dear R helpers, I have a curious problem, which is that a program I have written in R crashes R, unpredictably. When I say that the program crashes R, I mean that it causes R to terminate, completely. But, the...

Dear R-Helpers, I am hoping to perform survival analyses using the "ex-Gaussian" distribution. I understand that the ex-Gaussian is a convolution of exponential and Gaussian distributions for survival data. I checked the "survreg.distributions" help and saw...

Dear R Helpers, I am trying to extract the modulus from divisions by a sequence of fractions. I noticed that %% seems to behave inconsistently (to my untutored eye), thus: > 0.1%%0.1 [1] 0 > 0.2%%0.1 [1...

I thought one nice addition to a splom figure would be to have the scatterplots in the upper triangle and a color-coordinated correlation matrix on the bottom. So I tried my hand at customizing panel.pairs(), and was rebuffed...

I would be very grateful for help with devising the correct formula for an analysis with crossed random effects. The data consist of measurements of the width of a brain structure from 145 subjects, on both the right and left...

Dear R helpers, I wish to use the "sum" operator for each row of a data frame. However, it appears that the operator acts on the entire data frame, over all columns. What is the best way to obtain row...

Dear R Helpers, I want to test if a procedure within a loop has produced an error or not. If the procedure has produced an error, then I want to ignore its result. If it has not produced an error...

Deepayan, Thanks for the clarification. The rectangles are completely external to the panel data, and correspond to 90% confidence intervals built from training data, to be overlaid on these graphs of the test data. - Jonathan At 10:04 AM 7...

Dear R-Helpers, I want to compare the results of outputs from glmmPQL and lmer analyses. I could do this if I could extract the coefficients and standard errors from the summaries of the lmer models. This is easy to...

Dear R helpers, I am having trouble with an array inside a loop. I wish to accumulate the results of a function in an array within the function, over several loops of a program outside the function. The problem is...

I have a time series of data from an electroencephalogram (EEG). I wish to filter the data to get rid of 50Hz mains 'hum'. I have 'designed' a combination bandpass and notch filter using a web- site. The site returns...

Dear R Helpers I am having difficulty understanding how to use the penalty matrix for the nomROC function in package 'nonbinROC'. The documentation says that the values of the penalty matrix code the penalty function L[i,j] in which...

Dear R Helpers, I have noticed that when I use lmer to analyse data, the summary function gives different values for the AIC, BIC and log-likelihood compared with the anova function. Here is a sample program #make some data...

Dear R helpers, I would like to ask why polr occasionally generates results that look very odd. I have been trying to compare the power of proportional odds logistic regression with the Wilcoxon test. I generated random samples, applied both...

I am having great difficulty plotting what should be a simple graph. I have measured 1 'y' and 5 'x' variables in each of two groups. Linear regression shows significant differences in the slopes of the regression for each 'x...