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How can I compute a repeated measurement ANOVA with a mixed model?

Here we have an an experiment involving 20 subjects, each measured under two factors: Factor A (7 levels) and Factor B (3 levels). This results in 21 measurements per subject. Model Specification The ...
Robert Long's user avatar
2 votes
Accepted

ANOVA finding a main effect prevents inflation of Type I error rate

...these multiple comparisons do not inflate the Type I error rate because they are only conducted if the ANOVA finds a main effect. This is an example of right for the wrong reasons. Even if the ...
Frans Rodenburg's user avatar
1 vote

Formulating a mixed model with nested fixed and random effects

Answering this to help reduce the amount of unanswered questions. If I understand correctly, Batch and Day are crossed factors. ...
Robert Long's user avatar
1 vote

What is the best test to run to compare presence/absence of something between sampling locations?

I see two possibilities: A separate logistical regression per pathogen, with site as a predictor. A large model with both pathogen and site as predictors. In this case, you should account for the ...
Stephan Kolassa's user avatar
0 votes

How to interpret two way ANOVA repeated measurements results?

One problem in working with percentages as your outcome is that it doesn't take into account the number of observations. After all, you would believe more strongly that 10% is closer to the true ...
EdM's user avatar
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1 vote

Two-Way ANOVA or Mixed model

As an aside, we don't usually talk about data sets have axes, at least, not in my experience. Graphs have axes. Datasets have variables and observations. More importantly, you appear to be under a ...
Peter Flom's user avatar
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0 votes

Two-Way repeated measures ANOVA with multiple data points per measurement

Maybe not a complete answer, but a question, a comment, and some suggestions. Question: in order for your physicians to capture the medical history, they need some subjects (patients, real or ...
jginestet's user avatar
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3 votes

Multiple one-way ANOVAs, or are there better ways?

Indeed, you need a 2-way ANOVA. In fact you have a very nice full-factorial experimental design, with 6 replicates for each combination of factors (4 categorical peptides, 4 categorical conditions). ...
jginestet's user avatar
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1 vote

Can a Friedman's ANOVA be used for groups of different size?

It may give misleading results to omit reaction times for wrong answers. Instead this may be considered as right-censoring of reaction times for which a time-to-event (survival) analysis such as the ...
Frank Harrell's user avatar
0 votes
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Can a Friedman's ANOVA be used for groups of different size?

In general, Friedman's test is used for complete designs. The Skillings-Mack test might be a solution for you: it is a Friedman-type test for designs with missing data. More info about this test can ...
Mathemagician777's user avatar
2 votes
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Multiple one-way ANOVAs, or are there better ways?

Since there is a single, shared response variable for all comparisons you intend to do, I would try and incorporate this into a single model. This has the advantage of greater power and easier model ...
Frans Rodenburg's user avatar
0 votes

Hypothesis testing with control and treatment group - which statistical analysis to use?

If your data is arranged as it seems, then you can simply subtract the t1 measurement for each participant from the t2 measurement and then use a Student's t-test to compare the mean differences. That ...
Michael Lew's user avatar
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What is correct test to investigate difference between two conditions with repeated measures per subject?

I apoligize if I do not provide an answer to your question, but I see many issues with the overall experiment. I will try to list them below. Maybe you can clarify some of them, and I can then procide ...
jginestet's user avatar
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0 votes

What is correct test to investigate difference between two conditions with repeated measures per subject?

RM ANOVA makes assumptions that seem unlikely to be met here, primarily sphericity. One part of that is that all the covariances are equal. Also, RM ANOVA doesn't deal well with missing data, if you ...
Peter Flom's user avatar
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1 vote

How to interpret two-way anova results?

Maybe the easiest way to interpret a 2-way ANOVA (for that matter any ANOVA) is to realize that an ANOVA is fundamentally a linear regression. Thus, a significant p-value for the ANOVA means that ...
jginestet's user avatar
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2 votes

How to interpret two-way anova results?

Welcome to CV. If you click on the tag that is on your question, you will find extensive discussion of all sorts of questions about ANOVA. Very briefly, though: The fact that the main effects and the ...
Peter Flom's user avatar
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0 votes

Is a two way anova appropriate here?

Short answer; yes, you can use a 2-way ANOVA. You have 2 factors, 3 levels each. Of course, you need to confirm the basic assumptions of 2-way ANOVA (normality of residuals, homoscedasticity wrt fit). ...
jginestet's user avatar
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3 votes

Making 3 comparisons with a ternary variable

It is cumbersome to do all 15 comparisons between cells, as suggested by another answer. I think maybe you want to do 3 comparisons at each level of $x$. This can be done as follows: ...
Russ Lenth's user avatar
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Is it better to perform multiple paired t-test or One-Way ANOVA test

I am ignoring all issues regarding the specific details of the problem that were already addressed above, and just point that (basic) ANOVA assumes that the standard deviations of the two groups are ...
Yossi Levy's user avatar
0 votes

Using ANOVA for model comparison with a different ratio, how does it differ?

The two statistics $F$ and $F'$ have a one to one relationship $$F'(n-p_1) -F (p_2-p_1)= \frac{RSS_1}{\left(\frac{RSS_2}{n-p_2}\right)} - \frac{RSS_1-RSS_2}{\left(\frac{RSS_2}{n-p_2}\right)} = n- p_2$...
Sextus Empiricus's user avatar
3 votes

Making 3 comparisons with a ternary variable

Number of Comparisons If I understand correctly, you have two categorical variables, one with $2$ and and one with $3$ categories. You want to compare all combinations of categories ($2\times3 =6$). ...
Frans Rodenburg's user avatar
2 votes

ANOVA Type III understanding

The quoted passage you've come across highlights some important considerations when performing ANOVA, particularly regarding Type III sums of squares and the use of different contrast coding schemes. ...
Robert Long's user avatar
2 votes

One way ANOVA on compliance rates (by time period) with different lengths

As per the previous answer, yes, you can use an ANOVA (DV=compliance, continuous variable; IV=Group, catehorical, with 3 levels). But... Your sample size is very small (4, 5 and 3). It is unlikely you ...
jginestet's user avatar
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2 votes

One way ANOVA on compliance rates (by time period) with different lengths

You could do an ANOVA of lm(compliance ~ group) and then create a contrast of 1 vs. 2 and 3. This answers your question as posed. But you might consider using ...
Peter Flom's user avatar
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0 votes
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Multiple Linear Regression/ANOVA Help in Excel

told by someone else that I cannot run a multiple linear regression if my independent variables are constant. Indeed, there is not much you can do with this dataset (unless there is more too it than ...
Robert Long's user avatar
1 vote

Is it better to perform multiple paired t-test or One-Way ANOVA test

The Problem You want to see the effect of oxygen administration and whether that difference is affected by tissue type. This can be done with a linear model using an interaction, or by using a ...
Frans Rodenburg's user avatar
2 votes

Is it better to perform multiple paired t-test or One-Way ANOVA test

Unless I am missing something, the answer is in fact rather simple, and depends completely on the independence of the samples; is the tissue sample under "Normoxia, Tissua A, row 1", the ...
jginestet's user avatar
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