All Questions
24 questions
35
votes
3
answers
53k
views
How to get an "overall" p-value and effect size for a categorical factor in a mixed model (lme4)?
I would like to get a p-value and an effect size of an independent categorical variable (with several levels) -- that is "overall" and not for each level separately, as is the normal output from ...
- 1,345
15
votes
1
answer
16k
views
Conflicting results of summary() and anova() for a mixed model with interactions in lmer+lmerTest
I recently came across what I think may be a problem in how the anova() function from the lmerTest packages computes its F-...
- 451
6
votes
2
answers
2k
views
How to fix the threshold for statistical validity of p-values produced by ANOVAs?
I have run experiments on a group of users under two conditions, measuring the time it took users to finish their experiments. I used a cross-over design where half of the users started in the first ...
- 864
6
votes
1
answer
8k
views
Interpreting Two-way repeated measures ANOVA results: Post-hoc tests allowed without significant interaction?
I have conducted a study where I employed a two-way repeated measures design to investigate whether subjects respond to a main treatment effect. What I'm mainly interested in is whether subjects ...
- 61
5
votes
2
answers
796
views
Different results between ANOVA and Linear Mixed Effects
A set of subjects from two groups are requested to perform a test after a sleep session of type A and then after a sleep session of type ...
- 235
5
votes
1
answer
555
views
Paired and repeated measures! Now what? ANOVA or mixed model?
I have a simple setup. I have 10 patients and I would like to test the effect of a certain drug on kidney function. Each patient will serve as his own control and intervention.
First for the control ...
- 85
3
votes
2
answers
99
views
Testing changes in echocardiogram wave before and after treatment
I saw a couple of questions, very similar but unfortunately without any answer e.g.here and here. I aim to make it clear here with a dummy data hopefully, to receive some guidance
I would like to ...
- 1,158
3
votes
1
answer
66
views
What type of statistical analysis to perform?
I have an experiment with 10 subjects.
Each of them has to exert force and real-time feedback is received. Each subject experiences all 3 types of feedback (within-subject factor).
Moreover, each ...
- 60
2
votes
1
answer
5k
views
How to interpret the output of lmerTest::ranova in R?
I wanted to find the p-value of the random effect in a linear mixed model. I used ranova from lmerTest.
I am not sure how to ...
- 21
2
votes
1
answer
982
views
ANOVA with missing cells and multi-level analysis
I'm about to analyse some data (hypothesis testing) and would like some feedback on my approach as I have never seen this situation (missing cells in an ANOVA-like table). I would also like to know if ...
- 207
2
votes
1
answer
1k
views
Which statistical test : Anova or T-Test for between subject experiment (repeated measures ) with one IV with two levels( control and treatment)
It's a between-subject design with a control group and a treatment group with 50 people each. Each participant undergoes 100 trails. (repeated measures). So the only within-subject factor is the ...
- 71
2
votes
0
answers
198
views
Testing for between-samples factor with linear mixed models
I have data from an experiment including 5 biological replicates, each of which has 3 technical replicates. These 5 samples are divided into 2 groups (condition a and contidion b). My goal is to test ...
- 21
2
votes
0
answers
2k
views
Satterthwaite degrees of freedom in lmerTest for a 3x2x2 mixed model vs. mixed ANOVA dfs
I have traditionally been running my analyses using aov and would like to switch to lmer. My questions is whether or not this is ...
- 613
1
vote
2
answers
4k
views
Hypothesis testing with control and treatment group - which statistical analysis to use?
I would like some advice on what statistical analysis to use to test my hypothesis. I am using R. My setup is as follows (in .csv format, first line is header):
...
- 81
1
vote
1
answer
7k
views
Statistical test for paired data at multiple time points?
I have paired data (right and left measurements from the same subject) taken at different times. For the sake of the argument let's say the dependent variable (y) follows a normal distribution and we'...
- 857
1
vote
1
answer
55
views
Two way anova or paired t-tests
i am looking to see if there is a difference in dissolved oxygen levels between pool surface (S) and bottom (B) samples at four sites (an up and downstream site in two creeks). There are 3 replicate ...
- 11
1
vote
1
answer
35
views
Can I "discard" p-values from my linear mixed model?
I have a linear mixed effects model as follows in R:
model.int = lmer(value ~ group * category * time + (1|patient), data=modeldata)
anova(model.int) then gives me ...
- 11
1
vote
1
answer
195
views
Confusing main effect in mixed design ANOVA
I am conducting a mixed design ANOVA test using ezANOVA. I ran two different tests as follows:
Test1: within subject variable w, between subject variables age and x1.
Test2: within subject variable ...
- 535
1
vote
1
answer
906
views
Two Way Anova with Mixed Effects Model
I have been trying to understand the differences and relationship between fixed, random, and mixed effect models. I have found the following slides (link: http://www2.stat.duke.edu/~banks/111-lectures....
- 11
1
vote
1
answer
40
views
Interpreting Mixed Model ANOVA
In a 3 (condition) X 2 (time) mixed model ANOVA. If I hypothesised that anxiety in group A will increase from time 1 to time 2 and my results found no significant interaction but a significant main ...
0
votes
1
answer
44
views
Test for significant difference between two groups measured across time
I have two groups of time-dependent samples whose measured value changes nonlinearly with time. There are 3 samples in group A and 3 samples in group B. An example of my data is illustrated below.
...
- 1
0
votes
1
answer
366
views
Incorporating a random effect to the null model
I would like to decide if it is reasonable to include a factor variable to the null model I.e y ~ 1 VS y ~ (1|x)
I haver read this answer https://stats....
- 1,699
0
votes
0
answers
134
views
Random Effects ANOVA with test for difference in variances
Say I have a study measuring a continuous endpoint for 3 sample assays on two days, i.e. before and after intervention. The measurements are performed several times by different people (repeated ...
- 11
0
votes
0
answers
165
views
ANOVA comparison of non-significant mixed models
I have two nested mixed models: the difference in these models is the presence of one predictor variable (type). I used lmerTest ...
- 163