Displaying 20 results from an estimated 500 matches similar to: "ANOVA - more sophisticated contrasts"
2010 Sep 19
1
boyplots nearly identical but still highly significant effect?
dear list,
i am running a within-design ANOVA with 4 factors (4,4,2 and 2 levels each).
the last one is a time factor comprising two different treatment timepoints.
i fit a mixed-effects model using lme and apply the anova function to the
outcome. according to this analysis, there are highly significant main
effect on the first and the time factor. i then checked the boxplots for the
two 4-level
2009 Oct 25
3
Importing data from text file with mixed format
Hi,
I'm having difficulty importing my textfile that looks something like this:
#begin text file
Timepoint 1
ObjectNumber Volume SurfaceArea
1 5.3 9.7
2 4.9 8.3
3 5.0 9.1
4 3.5 7.8
Timepoint 2
ObjectNumber Volume SurfaceArea
1 5.1
2008 Apr 28
2
F values from a Repeated Measures aov
Hi Folks,
I have repeated measures for data on association time (under 2
acoustic condtions) in male and female frogs as they grow to adulthood
(6 timepoints). Thus, two within-subject variables (Acoustic
Condition: 2 levels, Timepoint: 6 levels) and one between-subject
variable (Sex:male or female).
I am pretty sure my distributions depart from normality but I would
first like to simply run a
2008 Mar 08
1
analysing mixed effects/poisson/correlated data
I am attempting to model data with the following variables:
timepoint - n=48, monthly over 4 years
hospital - n=3
opsn1 - no of outcomes
total.patients
skillmixpc - skill mix percentage
nurse.hours.per.day
Aims
To determine if skillmix affects rate (i.e. no.of.outcomes/total.patients).
To determine if nurse.hours.per.day affects rate.
To determine if rates vary between
2009 Sep 02
2
Average over data sets
Hello,
I have a number of files output1.dat, output2.dat, ... , output20.dat,
each of which monitors several variables over a fixed number of
timepoints. From this I want to create a data frame which contains the
mean value between all files, for each timepoint and each variable.
The code below works, but it seems like I should be able to do the
second part without a for loop. I played
2007 Jul 09
2
ANOVA: Does a Between-Subjects Factor belong in the Error Term?
I am executing a Repeated Measures Analysis of Variance with 1 DV (LOCOMOTOR
RESPONSE), 2 Within-Subjects Factors (AGE, ACOUSTIC CONDITION), and 1
Between-Subjects Factor (SEX).
Does anyone know whether the between-subjects factor (SEX) belongs in the
Error Term of the aov or not? And if it does belong, where in the Error Term
does it go? The 3 possible scenarios are listed below:
e.g.,
1.
2007 Nov 20
1
Vectorization/Speed Problem
Hi,
I cannot find a 'vectorized' solution to this 'for loop' kind of problem.
Do you see a vectorized, fast-running solution?
Objective:
Take the value of X at each timepoint and calculate the corresponding value
of Y. Leading 0's and all 1's for X are assigned to Y; otherwise Y is
incremented by the number of 0's adjacent to the last 1. The frequency and
2013 Apr 01
1
Help Please, ggplot2
library(ggplot2)
a<- read.table("data", header=T)
b = na.omit(a)
ggplot(data=b) + geom_line(aes(x=timepoint, y=value,group=sample, colour= factor(sample))) +? geom_point(aes(x=timepoint, y=value, group=s
ample)) + facet_wrap(~bio, scales = "free",ncol = 5) +theme_bw() + opts(legend.direction = "horizontal",??? legend.position = "top",????
2004 Apr 08
0
lme, mixed models, and nuisance parameters
I have the following dataset:
96 plots
12 varieties
2 time points
The experiment is arranged as follows:
A single plot has two varieties tested on it.
With respect to time points, plots come in 3 kinds:
(1) varietyA, timepoint#1 vs. variety B, timepoint#1
(2) varietyA timepoint #2 vs. varietyB timepoint #2
(3) varietyA timepoint #1 vs. variety A timepoint#2
- there are 36 of each kind
2010 Jun 10
1
do faster ANOVAS
Dear all R users,
I want to realize 800 000 ANOVAS and to store Sum of Squares of the effects. Here is an extract of my table data
Product attribute subject rep t1 t2 t3 … t101
P1 A1 S1 R1 1 0 0 … 1
I want to realize 1 ANOVA per timepoint and per attribute, there are 101 timepoints and 8 attributes so I want to realize 808 ANOVAS. This will be an ANOVA with two factors :
Here is one example:
2012 Feb 20
1
Reporting Kaplan-Meier / Cox-Proportional Hazard Standard Error, km.coxph.plot, survfit.object
What is the best way to report the standard error when publishing
Kaplan-Meier plots? In my field (Vascular Surgery), practitioners
loosely refer to the "10% error" cutoff as the point at which to stop
drawing the KM curve. I am interpreting this as the *standard error
of the cumulative hazard*, although I'm having a difficult time
finding some guidelines about this (perhaps I am
2005 May 15
1
CircStats and Anova
Hi,
If I have two sets of directional data (in radians) and want to compare them with a multifactorial anova.
Is it even legitimate to compare circular data with an anova? The books I've picked up from the library don't really say, but it looks unlikely.
If it is allowable, is my having stored the data as circular (X = as.circular(A)) something the aov() function will take into account,
2006 Oct 27
1
Censored Brier Score and Royston/Sauerbrei's D
System: R 2.3.1 on a Windows XP computer.
I am validating several cancer prognostic models that have been
published with a large independent dataset. Some of the models report a
probability of survival at a specified timepoint, usually at 5 and 10
years. Others report only the linear predictor of the Cox model.
I have used Harrell's c index for censored data (rcorr.cens) as a
measure of
2005 Aug 26
1
basic anova and t-test question
Hello,
I'm posting this to receive some comments/hints about a rather statistical than R-technical question ... .
In an anova of a lme factor SSPos11 shows up non-significant, but in the t-test of the summay 2 of the 4 levels (one for constrast) are significant. See below for some truncated output.
I realize that the two test are different (F-test/t-test), but I'm looking for for a
2004 Mar 18
1
two lme questions
1) I have the following data situation:
96 plots
12 varieties
2 time points
2 technical treatments
the experiment is arranged as follows:
a single plot has two varieties tested on it. if variety A on plot #1 has
treatment T1 applied to it, then variety B on plot #1 has treatment T2
applied to it. across the whole experiment variety A is exposed to
treatment T1 the same number of times as
2010 Apr 11
2
simple question about contrasts, lm and factors
I have a data frame with two variables that are factors. One is actually a
TRUE/FALSE factor, and I have coded it as 1/0, a continuous variable, but I
could turn it back into a factor. The second is an ordered factor and
consists of five timepoints. There are several continuous variables as well.
Now I want to fit a linear model to my data, using lm (or another R
procedure if recommended).
2008 Feb 05
1
Extracting level-1 variance from lmer()
All,
How does one extract the level-1 variance from a model fit via lmer()?
In the code below the level-2 variance component may be obtained via
subscripting, but what about the level-1 variance, viz., the 3.215072 term?
(actually this term squared) Didn't see anything in the archives on this.
Cheers,
David
> fm <- lmer( dv ~ time.num*drug + (1 | Patient.new), data=dat.new )
2007 Apr 18
1
undefined symbol: Rf_rownamesgets
I get the error
undefined symbol: Rf_rownamesgets
when I try to load my package, which include C++ code that calls that
function. This is particularly strange since the code also calls
Rf_classgets, and it loaded OK with just that.
Can anyone tell me what's going on?
For the record, I worked around this with the general purpose
attribute setting commands and R_RowNamesSymbol. I
2008 Sep 11
1
plot of all.effects object
All,
I'm trying to plot an all.effects() object, as shown in the help for
all.effects and also Crawley's R book (p.178, 2007). The data has a repeated
measures structure, but I'm using all.effects for the simple lm() fit here.
Below is a reproducible example that yields the error message.
fm.ex = lm(dv ~ time.num*drug*X, data = dat.new)
fm.effects = all.effects(fm.ex, xlevels =
2012 Jun 20
2
reshape
Hello, helpeRs,
I am attempting to reshape (either base R or package reshape) multiple .csv
spreadsheets from a very unfortunate wide format to long format. ?Each spreadsheet
looks something like this, after being read in to R:
toy <- data.frame(year = rep(2007:2008,each = 20), month = rep(1:5,each = 4, length = 40),
day = rep(1:2,each = 2,length = 40), hhmm = rep(1100:1101,length = 40),