Tagged Questions

"post-hoc" refers to analyses that are decided upon after the data has been collected, as opposed to "a priori".

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Post-hoc with Bonferroni a correction after ANOVA with repeated measure in SPSS

does somebody know where I can find the t value of post-hoc tests with Bonferroni correction when using SPSS.From what I get so far, I only see p values. Should I add a command in the script? Thank ...
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16 views

Testing and reporting interactions in multiple regression

I have a model with two between-participants predictors -- one continuous (a), and one categorical with two levels (b) -- and ...
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5 views

post-hoc testing in clustering analysis 1 feature

I've read that a post-hoc testing of the results of a clustering analysis is incorrect to perform. If I understood well this is true if the data are multidimensional and the purpose is to find out ...
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18 views

Can one make a Tukey post-hoc test for multiple regression in R and how?

I saw that the Tukey post-hoc test is usually done after performing an ANOVA. However, is it possible to carry it out in the case of multiple regression with the following model: ...
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17 views

Post-hoc power analysis of complex sample survey data

I am working with a complex sample survey data using Stata to determine the predictors of a given dependent variable. As part of my analysis result I want to report the post-hoc power for each ...
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0answers
8 views

Pairwise comparison of slopes from multivariate regression model in R

I am investigating size changes over time. I have five size variables in a multivariate linear model against year. I used the Anova() function in the car package to test whether the slopes are equal ...
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8 views

Follow up 2-way ANOVAs

I have a three-way significant interaction in a mixed-ANOVA, with two repeated-measures factors and one between-subjects factor. I would now like to follow it up with a repeated-measure ANOVA for each ...
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11 views

Post hoc for GLM that looks at interactions (in R)

I’d like some help with analysing some count data. I am very new to R (and statistical analysis for that matter!) and have done my best to work it out on my own … but seemed to have got stuck! I am ...
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28 views

How to use controls as a reference in GLM?

I'm running glms in R on two datasets, both with three discrete explanatory variables and one continuous dependent variable. My question is about the use of controls - I want to use my controls as a ...
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27 views

mixed design and simple main effect analysis in SPSS

Hope someone can help me. I have a within subject variable (Question, with 11 conditions) and a between subject variable (stimulation, with 3 conditions). I did an ANOVA and I obtained a main effect ...
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1answer
52 views

Which post-hoc is more valid for multiple comparison of an unbalanced lmer-model: lsm or mcp?

After doing a model comparison with my mixed lmer model, I have a model with three main effects, no interaction, say ...
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24 views

How do I report the result of an mcp-Tukey-test, i.e. how do I report it's z value?

After doing a model comparison with my mixed lmer model, I have a model with two main effects, no interaction, say signal ~ factor A + factor B + (1|subj). Factor ...
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30 views

GEE and post hoc comparisons

I am trying to analyze a dataset using the GEE. This is what I have so far ...
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0answers
30 views

Looking for a better post-hoc analysis

I'm a PhD student in Neuroscience, with a master degree in Psychology and I use R for my statistical analyses. As you know, in NHST usually post-hoc analysis in continuous data are essentially ...
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1answer
68 views

F stats for post hoc test of a linear mixed effects model

I have an unbalanced linear mixed effects model with three fixed factors of various levels and one random factor for my repeated measures data (for details see here). Thanks to your help I managed to ...
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2answers
44 views

Post hoc Scheffé test

My 1-way ANOVA test is not significant. Is it possible that a Scheffé test as a post hoc test be significant? If not, please say why not.
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1answer
56 views

Appropriate non-parametric post-hoc test for baseline comparisons?

I want to evaluate several "classifiers" (machine-learning algorithms) with paired samples. I do not want to compare each algorithms' performance to every other (n x m comparison) but only compare the ...
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1answer
28 views

Refitting with different contrasts vs. pairwise comparisons

Say, I fit a linear or generalised linear model in R with dummy coding (contr.treatment for ...
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1answer
25 views

Effect sizes for post-hoc paired comparisons in one-way ANOVA

Is there any alternative (like Cohen's d in t-test) to report about effect sizes for post-hoc paired comparisons in a one-way ANOVA (3 factor levels, correlated samples)?. Many thanks!!
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1answer
55 views

Mixed ANOVA post hoc analysis (and multiple comparisons)

I have a set of 12 subjects: 6 administred with drug A and 6 with drug B. For each subject two time-points have been collected (before and after drug treatment) for each analyte (over 6000). I had a ...
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2answers
108 views

Post-hoc tests for 2x2 ANOVAs (Type II & III) with interactions in R

I am trying to analyze data from an experiment using R and ran across a problem regarding the use of post-hoc tests with Type II & III ANOVAs. I only know of R functions that perform post-hoc ...
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21 views

GLM post hoc with non-parametric tests?

I have a question regarding the appropriate use of comparisons for independent samples (3 factor levels). Overall sample size is N=546, subsamples: 218 or 228 or 100), convenience sampling, ...
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1answer
109 views

Standard error bars overlap but significance - estimated marginal means versus observed means

I'm running a Mixed effects model ANOVA with two fixed factors (condition, repetition) and one random factor (subject). Subsequently, a Tukey multiple comparisons test is performed. Now I'd like to ...
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27 views

post hoc test other than Tukey of factorial Anova data in R

I am looking for help on post-hoc test of my group data (treatment and stage and interaction) after 2 way anova in R software. The data shown below is a example only actually my data shows significant ...
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25 views

Multiple comparisons, multidimensional data, several groups

Could you please help me with such a problem: Let's assume I have multidimensional data that consists of 30 samples and 10 variables. This is a 30x10 matrix. I have three groups of equal size (10 ...
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2answers
103 views

Post hoc test for object of class glmerMod in R?

I am running generalised linear mixed effects models in R using the lme4 package. I am wondering if there are any post-hoc tests available for models built using the glmer function? I know the ...
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2answers
68 views

Why is the Bonferroni correction properly used with planned, and not post hoc, contrasts?

The Wikipedia article on Post hoc analysis says "Bonferroni correction (This is properly used with planned, not post hoc, contrasts.)" but does not explain why the Bonferroni correction is properly ...
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50 views

Which post-hoc comparison to use and why

Hopefully this is now a much clearer picture of the question I want to answer: For each of 60 different plans I ran 35 simulation replications of my Agent Based Model (ABM) simulation. Then for each ...
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1answer
54 views

Post hoc selection of important features in random forest?

I want to guarantee a parsimonious random forest (few features used). What are methods to do this? It was suggested to me to get the feature importance after the model was created, and then create a ...
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1answer
102 views

Post hoc $\chi^2$ test with R

This is a quite simple question but I don't find any good, clear, precise answers: I'm looking for a way to perform post hoc test on a chi$^2$ test. I have 2 variables : var1 : good/fair/poor and ...
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2answers
305 views

Can Mann-Whitney test be used for post-hoc comparisons after Kruskal-Wallis?

I have a simulation where an animal is placed in a hostile environment and timed to see how long it can survive using some approach to survival. There are three approaches it can use to survive. I ran ...
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1answer
102 views

$\textit{Post hoc}$ test after repeated measures ANOVA (LME + Multcomp)

I have a dataset where the samples are dependent, belong to different groups, and measurements were taken over time. It looks like this: Subject Group Time Value S1 G1 12h 5.55 S1 G1 24h ...
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0answers
35 views

How can I perform a post hoc test of a three-way interaction in SPSS using the 'test' command?

I will describe the design of the experiment briefly. The task have two within-subject variables ($A$ and $B$), A. have two levels B. have three levels one repeated variable with 5 levels ('time ...
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96 views

How to test signicance of differences between factor levels in mixed model using lme4 in R

My basic knowledge on model simplification comes from Crawley (2007) and I have also looked in Zuur et al Mixed Effects Models and Extensions in Ecology with R to try to answer my question. In ...
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2answers
165 views

Post-hoc tests for MANOVA

I am using a MANOVA test to compare nine different dependent variables (from neuropsychological and neuropsychiatric assessment) between three groups. The output shows a significant influence from ...
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2answers
88 views

What does a post hoc power analysis say about the significance of the study results?

I orginially posted this over at AskMetafilter, and a commenter suggested I ask it here. I work for a dietary supplement company that also makes skin care products, and some of those skin care ...
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1answer
145 views

Cochran's Q & McNemar tests together

I have binomial outcome data for three groups that I am analyzing with Cochran's Q test. As discussed at this site, Cochran. However, I have to repeat this seven different times because I am ...
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42 views

Post hoc split plot design

I have an experiment in which I have four fenced large plots. I subdived every fenced plot into three smaller fences to have three grazing levels. Within every grazing level I planted 20 saplings ...
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32 views

Obtaining Cohen's d from z-test statistic

After an ANOVA, I run post-hoc tests with the glht function in the multcomp package. glht ...
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0answers
30 views

Follow up a significant interaction in ANOVA with dichotomous variables

Hopefully this is an easily answerable question, though I've been searching for an answer without any luck. I've run a 2x2x2x2 mixed-design ANOVA with two within-subjects and two between-subjects ...
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1answer
151 views

Doing post-hoc after a not significant interaction in mixed ANOVA

I conducted a mixed design ANOVA with two within-subjects factors: FactorA (2 levels), FactorB (2 levels), and one between-subjects factor: Group (2 levels). My main hypothesis regards the interaction ...
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0answers
23 views

Kruskal-Wallis test for factorial design [duplicate]

Is it possible to use the Kruskal-Wallis test for two factors and their interaction (i.e., two way ANOVA: Y~a*b)? And which post-hoc test is possible to use after ...
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1answer
92 views

R multcomp: contrasts for Tukey

I want to use the glht() function from package multcomp. In the linfct argument, I provide ...
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1answer
167 views

2x2 ANOVA, no main/interaction effects, post-hoc cell mean comparisons necessary/allowed?

I have a 2x2 between-subject design with unequal cell sizes. I ran an ANOVA with type I sums of squares to account for the unequal cell sizes. Neither of the two main effects nor the interaction ...
2
votes
2answers
120 views

How to find significant difference in a group/ ANOVA

Am I right to say that the results from the a repeated measures ANOVA does not tell you where a difference is in the group (if any)? So a post hoc test needs to be carried out? I'm using Stata to ...
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1answer
80 views

post-hoc test after logistic regression with interaction. Risk higher for type 1 or type 2 error?

I have a large data set (>1000 obs) and i'm performing regressions tests, both linear and logistic, on a series of clinical outcomes. In this test I verify the effect of interactions between two cat ...
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1answer
71 views

Post-hoc test for slopes - phia package for R

I am trying to do a post-hoc test to make pairwise comparisons between slopes. I found a package called phia but is not available for the R version 2.13.2. Does ...
2
votes
1answer
51 views

How to deal with non-normal heterocedastic data from a factorial experiment?

I ran an experiment with two factors each with two levels, 5 replicates each combination and one response variable. My data are non-normal and heterocedastic. Transformations didn't help. I ran a ...
0
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1answer
104 views

ANOVA and post-hoc analysis using R when we only have means and SD of three populations

I want to perform an ANOVA using R. I have three populations, represented by their respective means and SD: Pop.1: 5.5 +- 0.4 (n=100) Pop.2: 5.9 +- 0.3 (n=150) Pop.3: 6.2 +- 0.5 (n=200) Which is the ...
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0answers
52 views

Approach to post-hoc test for factors in a regressions (in R)

I have a problem with some analysis I need to do. I have a series of regressions. Some of the predictors of these regression are categorical with multiple levels. I performed regressions, both linear ...