similar to: Assumptions on Non-Standard F ratios

Hello, I am trying to create a plot often seen in hydrodynamic work than includes a contour plot representing the water speed with arrows pointing in the direction of flow. Does anyone have any idea how I might add arrows based on wf$angle (in the example below) to the plot below? Thanks in advance! Sam library(lattice) speed <- runif(100, 0, 20) wf <- data.frame(speed) wf$width <-

Hi all, I'd like to compare all levels of my interaction with each other. I read the pdf 'Additional multcomp Examples' but even though there is an example with an interaction it doesn't work for me when I want to compare within and between groups. Here is an example: #### d.fr<-data.frame(id=rep(1:16,3),treat1=rep(as.factor(LETTERS[1:3]),each=

Good Morning, I am trying to create a new column of character strings based on the first two letters in a string in another column. I believe that I need to use some combination of ifelse and grep but I am not totally sure how to combine them. I am not totally sure why the command below isn't working. Obviously it isn't finding anything that matches my criteria but I am not sure why. Any

Hi all, Two questions: 1. Is there a way to evaluate models from lmer() with a poisson distribution? I get the following error message: library(lme4) lmer(tot.fruit~infl.treat+def.treat+(1|initial.size),family=poisson)->model plot(fitted(model),resid(model)) Error: 'resid' is not implemented yet Are there any other options? 2. Why doesn't the function estimable() in gmodels

Hello all, I have not been able to find an answer to this problem. I feel like it might be so simple though that it might not get a response. Suppose I have a dataframe like the one I have copied below (minus the 'calib' column). I wish to create a column like calib where I am subtracting the 'Count' when 'stain' is 'none' from all other 'Count' data for

I have just realised that I sent this to Per only. For those interested on the list: -----Original Message----- From: Gygax Lorenz FAT Sent: Tuesday, September 14, 2004 4:35 PM To: 'Per Tor??ng' Subject: RE: [R] glmmPQL and random factors Hi Per, > glmmPQL(Fruit.set~Treat1*Treat2+offset(log10(No.flowers)), > random=~1|Plot, family=poisson, data=...) > > Plot is supposed

Hello, I am curious if anyone has had any success with finding a R version of a k-sample Kolmogorov-Smirnov test. Most of the references that I have able to find on this are fairly old and I am wondering if this type of analysis has fallen out of favour. If so, how do people tend to compare distributions when they have more than two? Is it reasonable to pursue an adjusted p-value method. That is,

Hello all, I have a fairly simple data manipulation question. Say I have a dataframe like this: dat <- as.data.frame(runif(7, 3, 5)) dat$cat <- factor(c("1","4","13","1","4","13","13A")) dat runif(7, 3, 5) cat 1 3.880020 1 2 4.062800 4 3 4.828950 13 4 4.761850 1 5 4.716962 4 6

Hello All, I try to use the attached code to produce a cross over plot. There are 13 subjects, 7 of them in for/sal group, and 6 of them in sal/for group. But in xyplot, all the subjects are listed in both subgraphs. Could anyone help me figure out how to get rid of the empty levels? Thanks library(lattice) pef1 <- c(310,310,370,410,250,380,330,370,310,380,290,260,90) pef2 <-

Hello, I am having a little trouble formatting my dates correctly. When I plot something using the following commands, R plots the most recent date on the left of the figure and then earlier date on the right of the figure. Given that English is read from left to right I would like to have the dates on my figure arranged in the same way. I am sure that this is something fairly simple but I was

I don't know if this is the best place to post this question but I will try anyway. I have two experiements for which I use one-way matched-randomized ANOVA for the analysis and I would like to compare different treatments in the two experiments. The only common group in the two experiments are the controls. Is there any ANOVA design that allows me to make this comparison taking into

Hello there, I have a situation where I would like to select the first row of a particular factor for a data frame (data example below). So that is, I would like to select the first entry when the factor1 =A and then the first row when factor1=B etc. I have thousands of entries so I need some general way of doing this. I have a minimal example that should illustrate what I am trying to do. I am

Hello, I have a question about working with dates in R. I would like to summarize a response variable based on a designated and irregular time period. The purpose of this is to compare the summarized values (which were sampled daily) to another variable that was sampled less frequently. Below is a trivial example where I would like to summarize the response variable dat$x such that I have average

Hi, please excuse the most likely very trivial question, but I'm having no idea where to find related information: I try to recapitulate very simple plotting behavior of Excel within R but have no clue how to get where I want. I have tab delimited data like cell treatment value line a treat1 4 line a treat2 3 line b treat1 8 line b treat2 11 I'd like to have a plot (barplot), that

Hello, I am attempting to write a script that adds error bars to a barchart. I basing my attempt heavily on the following thread: http://tolstoy.newcastle.edu.au/R/e2/help/06/10/2791.html I can't seem to get around the problem that was discussed in the thread. The following example should illustrate my problem. Sorry about the messy example but I am 1) trying to make it as close as possible

Hi all! I have 4 treatments on 5 animals Treat1 Treat2 Treat3 Treat4 Animal1 36 37 35 39 Animal2 33 34 36 37 Animal3 37 35 33 38 Animal4 34 36 34 35 Animal5 35 36 33 36 I use an Anova and i try to verify calcul So i retrieve: DF SS

Dear R users, I have a linear model of the kind outcome ~ treatment + covariate where 'treatment' is a factor with three levels ("0", "1", and "2"), and the covariate is continuous. Treatments "1" and "2" both have regression coefficients significantly different from 0 when using treatment contrasts with treatment "0" as the

Hi, I have a simple dataset with repeated measures. one factor is treatment with 3 levels (treatment1, treatment2 and control), the other factor is time (15 time points). Each treatment group has 10 subjects with each followed up at each time points, the response variable is numeric, serum protein amount. So the between subject factor is treatment, and the within subject factor is time. I ran a

Hello R list, This is a question for anyone who has used the by() command. I would like to perform a regression on a data frame by several factors. Using by() I think that I have able to perform this using the following: > lm.r <- by(master, list(Sectionf=Sectionf, startd=startd), function(x) lm (tot.c ~ starttime, data = x)) So that is, I would like to perform separate regressions for

Hi all: I have 3 questions about the poisson regression of contingency table. Q1¡¢How to understand the "independent poisson process"as many books or paper mentioned? For instance: Table1 ------------------------------------------- treat caner non-cancer sum ------------------------------------------- treat1 52(57.18) 19(13.82) 71 treat2