similar to: sample within groups-slight problem

We are doing a power analysis by generating noisy data sets according to a model, fitting the model to the data, and extracting a p-value. What is the best way to do this many times? We are just using for loops and it is too slow because we are repeating the analysis for many parameterizations. I can think of several ways to do this: for loop sapply using the plyr package using the lme4 package

Hi everyone, I've got a question concerning the function acf(.) in R for calculating the autocorrelation in my data. I have a table with daily returns of several stocks over time and I would like to calculate the autocorrelation for all the series (not only for one time series). How can I do this? After that I want to apply an autoregressive model based on the estimated lag in the

Hello all, So I am using the (formula entry) method for randomForests: randomForest(y~x1+x2+...+x39+x40,data=xxx,...) but the issue is that some of the items in that package dont take a formula entry - you have to explicitly state the y and x vector: randomForest(x=xxx[,c('x1','x2',...,'x40')],y=xxx[,'y'],...) Now my question is whether there is a function/way

I have a matrix called mat and y is the column number of my response and x is a vector of the column numbers of my terms. The variable name of y can change, so I don't want to hardcode it. I can find out the name as follows: > names(mat)[y] [1] "er12.l" Then I can run the regression by hard coding the variable name as follows: > mod <-

Hello, The function barplot automatically creates a y-axis that doesn't necessarily cover the range of y-values to be plotted. I know how to manually create my own y-axis so that it does cover the range, but I was wondering if there is some parameter to change so that the scale of the y-axis is automatically taller than the tallest bar. I thought setting xpd=F would do it, since it says that

Dear List: I have the following simple program: x<- sample(site) VarGuilda1<- var(tapply(x,site,func1)) VarGuilda2<- var(tapply(x,site,func2)) VarGuilda3<- var(tapply(x,site,func3)) VarGuilda4<- var(tapply(x,site,func4)) VarGuilda5<- var(tapply(x,site,func5)) VarGuilda6<- var(tapply(x,site,func6)) VarGuilda7<- var(tapply(x,site,func7)) VarGuilda8<-

Hello, My question likely got buried so I am reposting it in the hopes that someone has an answer. I have thought more about the question and modified my question. I hope tha my specific question is: I am attempting to create a bootstrap procedure for a finite sample using the theory of Rao and Wu, JASA (1988) that replicates within each strata (h) n_h - 1 times. To this end, I require a

Full_Name: Peter Gedeck Version: R1.6.2 and R1.7.0 OS: Windows XP Submission from: (NULL) (194.191.169.72) Hello, I marked the bug report Private, as I don't want my email address on the web server. The problem that I found is best explained using an example. index <- 1:6 cluster <- c(1,1,1,2,2,3) tapply(index,cluster,sample) gives $"1" [1] 2 1 3 $"2" [1] 4 5

How would one go about putting titles in each of several plots that are generated from within a call to tapply? For example I'd like the following two barplots to have titles 'Group 1' and 'Group 2', where '1' and '2' come from the levels of 'group'. group <- gl(2, 10) result <- sample(c('A', 'B'), size=length(group),

Hi, people. I am using R-2.5.0 now, when tried the function aggregate with sum, it showed an error as following: > a <- gl(3,10) > b <- rnorm(30) > aggregate(b,list(a),sum) # here is the error message, it complained that an error in FUN(X[[1L]], missing "INDEX", and no defaults value. but the tapply function will be okay. > tapply(b,list(a),sum) 1 2

Dear List, I'm an [R] novice starting analysis of an ecological dataset containing the basal areas of different tree species in a number of research plots. Example data follow: > Trees<-data.frame(SppID=as.factor(c(rep('QUEELL',2), rep('QUEALB',3), 'CORAME', 'ACENEG', 'TILAME')), BA=c(907.9, 1104.4, 113.0, 143.1, 452.3, 638.7, 791.7, 804.3),

Hello! I have a data frame with a factor and a numeric variable: x<-data.frame(factor=c("b","b","d","d","e","e"),values=c(1,2,10,20,100,200)) For each level of "factor" - I would like to divide each value of "values" by the mean of "values" that corresponds to the level of "factor" In other

Hello, I'm facing a rights issue on with Asterisk 11.3.0 running on CentOS release 5.8. Asterisk process is running with asterisk since it is define in asterisk.conf as following: runuser = asterisk rungroup = asterisk You can see asterisk proccess here: ps aux |egrep 'python|asterisk' root 11581 0.0 0.1 65940 600 ? S Apr17 0:00 /bin/sh /usr/sbin/safe_asterisk

Dear list, I have a data.frame with x, y values and a 3-level factor "group", say. I want to create a new column in this data.frame with the values of y scaled to 1 by group. Perhaps the example below describes it best: > x <- seq(0, 10, len=100) > my.df <- data.frame(x = rep(x, 3), y=c(3*sin(x), 2*cos(x), > cos(2*x)), # note how the y values have a different

This one should be easy but it's giving me a hard time mostly because tapply puts the results in a list. I want to calculate the cumulative sum of a variable in a dataframe, but with the accumulation only within each level of a factor. For a very simple example, take: > df <- data.frame(x=c(rep(1,5),rep(2,5),rep(3,5)),fac=gl(3,5,labels=letters[1:3])) > df x fac 1 1 a 2 1 a

Colegas: Necesito hacer una serie de ajustes de un modelo de decaimiento exponencial a unos datos de concentración de compuestos fluorescentes contra el tiempo. Para la mayoría de los experimentos tengo tres réplicas por cada tiempo, y haciendo los gráficos correspondientes parece haber diferencias muy grandes en la dispersión de los datos, siendo generalmente mas grandes al principio del

Hello, I am seeking advice regarding how I might add the prefix " kc$ " to variables in a series of commands. The complication is that there is a large number of variables with different commands. Examples of the variables in typical commands follow. It is simple to use search & replace for common variables such as "group" but I would appreciate advice about whether

Sobre todo explicarles bien a que pregunta quieren contestar con la estadistica etc. El tema en psicología es sore todo que entiendan cuando leen algún articulo que significa la estadística. Por eso creo que con execsl y su add va super bien para que puedan reproducir casos. Usar algo nuevo, por lo que he visto con los chVales de clase les pierde por completo y desconectan. Ademas la estad lA

Hello, I have been looking for functions for calculating the within-groups variance and between-groups variance, for the case where you have several numerical variables describing samples from a number of groups. I didn't find such functions in R, so wrote my own versions myself (see below). I can calculate the within- and between-groups variance for the Sepal.length variable (iris[1]) in

Hi, all I have a rather un-ideal dataset that I am trying to work with, and would appreciate any advice you have on the matter. I have 4 years worth of data taken at 3 depth-zones from which samples have been taken at random. I am looking at the abundance of organism A between depth zones and across years, and am interested in the possible interaction of organism A distributions shifting