search for: trials

I'm trying to learn how to do a repeated measures ANOVA in R using lme(). A data set that comes from the book Design and Analysis has the following structure: Measurements (DV) were taken on 8 subjects (SUB) with two experimental levels (GROUP) at four times (TRIAL). In SAS, I use the code: PROC MIXED DATA=[data set below]; CLASS sub group trial; MODEL dv = group trial group*trial;

...aximum the median outcome time for that particular trial). I have started by pre-allocating a matrix which has 3 columns; one for trial number, one for patient number, and I want to complete the third with the results of the uniform simulation. For example, I have : n<-10 ## patients per trial trials<-3 ## 3 trials outcome<-matrix(NaN,nrow=n*trials,ncol=3) for(i in 1:trials){ outcome[,1]<-rep(1:trials,each=n) outcome[,2]<-rep(1:n) } In the third column, for each trial I want to create n sets of random draws: runif(n,0,median[i]), where median[i] is the median outcome time in th...

...ition + Distance, random = ...) the question is how do I organize the random statement? Is it: random = ~1 | Subject random = ~1 | Subject/Trial random = ~1 | Trial/Subject random = ~1 | Condition/Distance/Subject/Trial ...etc, or something else entirely? Mostly I'm unclear about whether the Trials should be grouped under subject because I expect the trials to be more similar within a subject than across subjects, or whether subjects should be grouped under trials because the trials are going to differ depending on the subject. If trials should be grouped under subjects, then do the cond...

I am extremely puzzled by this behavior in R. I have a data frame called Trials in which I have results from an experiment. I am trying to do a subjects analysis, but getting weird results. Each row has 1 trial in it, which includes a column for the subject number I get the list of subject numbers like so: > Subj=unique(sort(Trials$Subj)) Then I loop over them. But I get...

Hello, I have been struggling for quite some time to find a solution for the following problem. I have a data frame which is organized by block and trial. Each trial is represented across several rows in this data frame. I'd like to extract the first x rows per trial and block. For example block trial x y 1 1 1 605 150 2 1 1 603 148 3 1 1 604 140 4 1 1 600 140 5 1 1 590 135 6 1 1 580 135 7

Hi, I am create a new DF that summarizes the mean angle per treatment/trial, of the original DF (see below). I have had some success using: (tapply(df$Angle, INDEX=interaction(df$State, df$Trial), FUN=mean)); however, this gives the answer as a list, which means I would have to split the name to get the categories back. Does anyone know a simple way to transform the Original DF into Summary

My name is Giovanna and I am a PhD student in Norway. I am a beginner with statistics and R, hence my ignorance. Apologies from now..... I have been collecting data on time performances of 5 subjects using a 1:3 scale tower yarder. The task was consisting in yarding 5 small logs placed on permanently marked course. Four subjects had different previous experiences (None, Some) and the fifth was a

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Dear R users, I recently stumbled upon problems of reproducibility while running GAM analyses in different R and gam package versions. In the example below, a small dataset is created in which the y and x1 variables are 100% correlated. The intents of this example were primarily for regression testing and, secondarily, to evaluate how the gam algorithm behaves under extreme/limit conditions. I

...s code worked fine for me, then did some cleaning up of formatting using ESS (Emacs) and now I get this error, no idea what is causing it, all the brackets/parentheses seem to be balanced. What have I done wrong? Thanks Jim p0.trial01 <- 0.25 TruOR01 <- 0.80 num.patients.01 <- 50 num.trials.01 <- 5 LOR01.het.in <- 0.00 num.sims <- 1 simLOR01 <- vector(length=num.trials.01) simLORSE01 <- vector(length=num.trials.01) simOR01 <- vector(length=num.trials.01) trialnum01 <- vector(length=num.trials.01) x0count <- vector(length = num.trials.01) x1count <- vector(...

I'm trying to get the following section of code to work, I think the problem is being caused by the assignment of data to the lm function not evaluating to "train" in the parent environment but I can't seem to figure out how to do this. fitmodel <- function(trial,data) { wrap.lm <- function(formula,data,...) { cat("in wrap lm",NROW(data),"\n");

Hi, I'm working with step.gam in gam package. I'm interested both in spline and lowess functions and when I define all the models that I'm interested in I get something like that: > gam.object.ALC<-gam(X143S~ALC,data=dane,family=binomial) >

Hi list, I have a function that detects saccadic eye movements in a time series of eye positions sampled at a rate of 250Hz. This function needs three vectors: x-coordinate, y-coordinate, trial-id. This information is usually contained in a data frame that also has some other fields. The names of the fields are not standardized. > head(eyemovements) time x y trial 51

...to the R program, and I hope some of you can offer me some suggestions on how to organize my data in R using some of the more advanced data structuring technique. Here's my scenario: I have date set of 50 participants (each with conditions and demographic data), each participant performed 2x16 trials, for each trial, there was specific information about the trial (i.e. errors, and timing), and a spreadsheet-like large data set with headers. I have to extract data from each spreadsheet-like data according to the information about the specific trial. And then group then according to trial nature...

Dear all, I'm a newbie in R. I have a 45x2x2x8 design. A dataframe stores the metadata of trials. And each trial has its own data file: I used "read.table" to import every trial into R as a dataframe (variable). Now I dynamically ask R to retrieve trials that fit certain selection criteria, so I use "subset", e.g. tmptrialinfo <- subset(trialinfo, (Subject==24 & Fil...

Hello everybody! I use R 1.6.2 in Windows, and have a problem controlling the na.action. In a dataset with twelve trials, one of the trials lack any readings of the variable "STS.SH" (standing power at harvest) Fitting an aov() object with the call: led1t7sts.aov <- aov(STS.SH ~ Trial/Block + Treatment + Treatment:Trial, data = led1t7, na.action=na.exclude) seems to work as it produces an object with...

Hello, As I am new with R I am completely stuck in resolving a, no doubt, easy problem. I have a dataset with an enormous amount of rows and 17 columns. I need to know per trial and subject number if another variable (tt) exceeds a maximum. If this is true than the last 5000 rows of that specific trial for that subject number needs to be deleted. But I am completely stuck on how to do so.

...experience the event during the trial; After period of time those subjects were randomized to 3 treatments again in trial 2, but different from what they got in 1st trial, some of them experience the event during the 2nd trial (I think the carryover effect can be ignored since the time between two trials is long enough.) What I am interested is whether the survival functions differ among treatments. How should I deal with the correlation between the observation since the same subject was treated with two different drugs in two trials? Should I add "TRIAL" , "whether the event happen...

Here is a runable program. When I plot Day and Wgt, it graphs all the data points. All I need is daily.sub1 plotted. I also need each "Tanks" to have its own col or pch. When I run it with the line with pch, it gives me nothing. rm(list=ls()) Trial<-rep(c(1,2),each=12) Tanks=rep(c("a3","a4","c4","h4"),each=3,2) Day=rep(c(1:12),2)

Hi folks, I am trying to figure out how run a repeated measures ANOVA on the following data set. subject trial frequency dplvl 1 FSI052A A 1 NA 2 FSI052B B 1 NA 3 FSI053A A 1 NA 4 FSI055A A 1 NA 5 FSI055B B 1 NA 6 FSI057A A 1 NA 7 FSI057B B 1 NA 8 FSI058A A 1 NA 9