Displaying 20 results from an estimated 200 matches similar to: "t-test or ANOVA...who wins? Help please!"
2011 Jan 05
3
Assumptions for ANOVA: the right way to check the normality
Dear all,
I would like to know which is the right way to check the normality assumption
for performing ANOVA. How do you check normality for the following example?
I did an experiment where people had to evaluate on a 7 point scale, the degree
of realism of some stimuli presented in 2 conditions.
The problem is that if I check normality with the Shapiro test I get that the
data are not
2011 Jan 05
2
Problem with 2-ways ANOVA interactions
Dear All,
I have a problem in understanding how the interactions of 2 ways ANOVA work,
because I get conflicting results
from a t-test and an anova. For most of you my problem is very simple I am sure.
I need an help with an example, looking at one table I am analyzing. The table
is in attachment
and can be imported in R by means of this command:
scrd<-
2007 Jul 31
1
how to sort dataframe levels
Hi everyone,
I've been bashing my head against this for days now, and can't figure out
what to do.
I have the following dataframe
header appetitive stimulus aversive stimulus chaining
contingency discriminative stimulus extinction intermittent
reinforcement negative reinforcer operant response place
learning positive reinforcer punishment reinforcement
2011 May 21
0
Problem with ANOVA repeated measures: "Error() model is singular"
Hello everybody,
I need an help because I don´t know if the command for the ANOVA analysis I am
performing in R is correct. Indeed using the function aov I get the following error:"In aov (......) Error() model is singular"
The structure of my table is the following: subject, stimulus, condition, sex, response
Example:
subject stimulus condition sex response
2004 Jan 16
0
anova repeated measure interpretation
Dear all,
I have tried to use R for the repeated measures
experiment design in a phonetic study, and in the
resulting forms I met some problems which perturb the
final interpretation of the results.
I will explain the experiment design first:
the same 7 subjects were answering a question about 25
linguistic stimuli; the stimuli were the same
utterances which were processed in 3 different
ways (3
2011 Jan 05
1
Comparing fitting models
Dear all,
I have 3 models (from simple to complex) and I want to compare them in order to
see if they fit equally well or not.
From the R prompt I am not able to see where I can get this information.
Let´s do an example:
fit1<- lm(response ~ stimulus + condition + stimulus:condition, data=scrd)
#EQUIVALE A lm(response ~ stimulus*condition, data=scrd)
fit2<- lm(response ~ stimulus +
2013 Feb 25
1
creating variable that codes for the match/mismatch between two other variables
Dear all,
I have got two vectors coding for a stimulus presented in the current trial (mydat$Stimulus) and a prediction in the same trial (mydat$Prediciton), respectively.
By applying an if-conditional I want to create a new vector that indicates if there is a match between both vectors in the same trial. That is, if the prediction equals the stimulus.
When I pick out some trials randomly, I get
2006 Mar 22
1
mixed ordinal logistic regression
Dear Colleagues,
I hope to know how ordinal logistic regression with a mixed model is made
in R. We (My colleague and I) are studying the behavior of a beetle. The
attraction of beetles to a stimulus are recorded: the response is Slow,
Mid, or Fast. They are based on the time after the presentation of the
stimulus to the beetles. Because we do not observe the behavior
continuously but do
2011 Jan 07
2
anova vs aov commands for anova with repeated measures
Dear all,
I need to understand a thing in the beheaviour of the two functions aov and
anova in the following case
involving an analysis of ANOVA with repeated measures:
If I use the folowing command I don´t get any problem:
>aov1 = aov(response ~ stimulus*condition + Error(subject/(stimulus*condition)),
>data=scrd)
> summary(aov1)
Instead if I try to fit the same model for the
2011 Jan 09
2
Post hoc analysis for ANOVA with repeated measures
Dear all,
how can I perform a post hoc analysis for ANOVA with repeated measures (in
presence of a balanced design)?
I am not able to find a good example over internet in R...is there among you
someone so kind to give
me an hint with a R example please?
For example, the aov result of my analysis says that there is a statistical
difference between stimuli (there are 7 different stimuli).
...I
2013 Jan 10
0
mgcv: Plotting probabilities for binomial GAM with crossed random intercepts and factor by variable
mgcv: Constructing probabilities for binomial GAM with crossed random
intercepts and factor by variable
Hello,
(I'm sorry if this has been discussed elsewhere; I may not have been
looking in the right places.)
I ran a binomial GAM in which "Correct" is modelled in terms of the
participant's age and the modality in which the stimulus is presented
(written vs spoken).
2012 Aug 03
0
MANOVA with repeated measures in R
Dear list member,
I deperately need an help in performing a MANOVA in R, but I encountered some
problems both in the design and in the synthax with R.
I conducted a listening experiment in which 16 participants had to rate the audio
stimuli along 5 scales representing an emotion (sad, tender, neutral, happy and aggressive).
Each audio stimulus was synthesized in order to represent a
2005 Dec 01
1
LME & data with complicated random & correlational structures
Dear List,
This is my first post, and I'm a relatively new R user trying to work out a
mixed effects model using lme() with random effects, and a correlation
structure, and have looked over the archives, & R help on lme, corClasses, &
etc extensively for clues. My programming experience is minimal (1 semester
of C). My mentor, who has much more programming experience, but a comparable
2006 May 11
2
greco-latin square
Hi,
I am analyzing a repeated-measures Greco-Latin Square with the aov command.
I am using aov to calculate the MSs and then picking by hand the appropriate
neumerator and denominator terms for the F tests.
The data are the following:
responseFinger
mapping.code Subject.n index middle ring
little
----------------------------------------------------------------------------
1 1
2007 Aug 02
1
ggplot2 qplot and add
Hi there,
I have some simple frequencies I want to plot into one graph. I had it
working, and now I can't figure out whats going wrong. All the data is
stored in a dataframe, and i finally managed to order the factor correctly!
Each column is a variable and contains integers for the same set of values
in the column that contains the headers for each row (graphLabels).
So, I get the data
2003 Jun 11
1
COX PH models for event histories?
This is a question about the use of the Cox proportional hazards model to analyze event histories.
I am looking at the responses of sympathetic nervous system activity to a stimulus. The activity I observe is a burst that can only occur once per heart beat cycle (e.g., a binary count). Typically bursts occur in 60-80% of the heart cycles * sensory stimuli can modify these burst probabilities.
2011 Oct 07
1
ANOVA/ANCOVA Repeated Measure Mixed Model
Hello,
I am trying to test some results I have for significance. It has been
recommended that I use R and I am completely new to this.
Set-up:
Groups: two groups of 8 subjects (16 total)
Two conditions: alert and passive
Measurements: responses for three different stimuli (A, B, and C)
measured in each condition
Experiment: Testing the order of conditions
Group one: Alert A, B
2011 Jan 08
1
Anova with repeated measures for unbalanced design
Dear all,
I need an help because I am really not able to find over internet a good example
in R to analyze an unbalanced table with Anova with repeated measures.
For unbalanced table I mean that the questions are not answered all by the same
number of subjects.
For a balanced case I would use the command
aov1 = aov(response ~ stimulus*condition + Error(subject/(stimulus*condition)),
data=scrd)
2003 Nov 25
1
problem plotting curve through data
I'm having trouble plotting a curve (basically a dose-response
function) through a set of data.
I have created a dataframe (df) of Stimulus Intensities (xstim) and
Normalized Responses (yresp), and I've used nls() to calculate a nonlinear
regression, like so:
--------------------
> f <- yresp ~ xstim^n / (xstim^n + B^n)
> starts <- list(n=.6, B=11)
> myfit <-
2006 Dec 16
2
how to adjust link function in logistic regression to predict the proportion of correct responses in 2AFC task?
I have would like to use logistic regression to analyze the
percentage of correct responses in a 2 alternative forced
choice task. The question is whether one needs to take into
account the fact expected probabilities for the percentage of
correct responses ranges between 0.5 and 1 in this case and
how to adjust the link function accordingly in R (see details below).
Gabriel
Subjects were asked