Tagged Questions
1
vote
0answers
22 views
How to Partition An Interaction SS in ANOVA
I'm a new user of R and I'm trying to replicate Table 6.18 on page 262 in Statistical Procedures in Agricultural Research, By K. A. Gomez and A. A. Gomez. New York, Chichester, etc.: Wiley (1984). ...
0
votes
0answers
34 views
How to avoid regression to the mean in a simple comparison
This is a pretty simple question but I haven't been able to find a clear answer to it. I have some data from a behavioral experiment taken under two conditions (A and B); within each condition, each ...
0
votes
1answer
107 views
Checking confidence intervals on user defined contrast (one-way ANOVA)
Hi is anyone able to help - I am doing this all in R Code:
I have run one way analysis on some data and set up 2 contrasts (Liberarts-Finearts and also Engineering-science). I now need to calculate ...
3
votes
2answers
282 views
Effect size in contrast analysis
I'm running 2-way repeated measures ANOVA (3 and 5 levels) with planned contrasts afterwards. I'm interested in comparing
1)levels of the first factor among themselves (e.g. A1B with A2B, A2B with ...
1
vote
0answers
155 views
Orthogonal contrasts in R
I am having somewhat of a problem setting up contrasts from an anova in R. I have done this in the past, but at the moment I don't seem to be able to get R to use my contrast matrix instead of the ...
3
votes
1answer
301 views
Contrasts in repeated mesures ANOVA in R
I am a refugee from SPSS in the process of re-learning how to do everything in R. Mostly it's been fun, as R is great for a lot of things but I've run into a snag that I can't seem to find a solution ...
1
vote
1answer
296 views
4
votes
2answers
295 views
How to interpret these custom contrasts?
I am doing a one way ANOVA (per species) with custom contrasts.
...
6
votes
2answers
198 views
Refugee from SPSS having issues with fit.contrast in R
I'm trying to wean myself off of SPSS and switch to R for psych statistics and I'm mostly getting there, but I've run into a real roadblock with fit.contrast from ...
2
votes
0answers
140 views
How to test and examine interaction effect in 2 by 3 by 6 mixed ANOVA design?
Background:
I have two groups of children - one group with normal hearing and one with permanent hearing losses - call them NH and PHL.
Each child has had a hearing test, consisting of 6 different ...
3
votes
2answers
3k views
What if an overall ANOVA is not significant, but specific contrasts are?
Study Design: I have a 2x3 factorial design, 2 levels of Time (2050 or 2100) by 3 levels of information (None/Control, Moderate, Extreme).
I set up some very specific contrasts when analyzing this ...
1
vote
0answers
258 views
Contrast to ANOVA with interaction term
I need to fit orthogonal contrasts to the following model. The following example data.
...
7
votes
1answer
776 views
How to perform a 4 by 4 mixed ANOVA with between- and within-subjects contrasts using R?
Beginner user of R here struggling with a repeated measures ANOVA.
I have a dataset that consists of one between subjects factor with 4 levels (coded in a single variable called 'groups'), and one ...
7
votes
2answers
2k views
How to specify specific contrasts for repeated measures ANOVA using car?
I am trying to run a repeated measures Anova in R followed by some specific
contrasts on that dataset. I think the correct approach would be to use
Anova() from the ...
2
votes
3answers
331 views
Are linearly dependent contrasts permitted when performing planned comparisons in within-subjects ANOVA?
Here it says that planned comparisons should be linearly independent.
Here (page 13) and elsewhere I see people giving examples of linearly dependent contrasts.
How should this conflicting advice ...
6
votes
1answer
5k views
Post hoc test after ANOVA with repeated measures using R
I have performed a repeated measures ANOVA in R, as follows:
aov_velocity = aov(Velocity ~ Material + Error(Subject/(Material)), data=scrd)
summary(aov_velocity)
...
4
votes
1answer
970 views
How to setup and interpret ANOVA contrasts with the car package in R?
Let's say I have a simple 2x2 factorial experiment that I want to do ANOVA on. Like this, for example:
...
11
votes
4answers
4k views
How does one do a Type-III SS ANOVA in R with contrast codes?
Please provide R code which allows one to conduct a between-subjects ANOVA with -3, -1, 1, 3 contrasts. I understand there is a debate regarding the appropriate Sum of Squares (SS) type for such an ...
