"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 test on a Poisson regression

Question How can I perform a post-hoc test after a Poisson regression to know which group differ from which other group? Dummy Data Here are some dummy data (coded in ...
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53 views

Post hoc power analysis for a non significant result?

I have submitted a paper to a journal reporting a non-significant finding. One of the reviewers has asked me to include a power analysis on my data to work out how big a sample size I would need to ...
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37 views

Interpretting non-contiguous significance letters from Tukey HSD test in the multcomp package? [closed]

I've only ever seen the compact letter display for Tukey's HSD give contiguous letter groupings but like in the following example this package is giving non-contiguous groupings (ie 'cde' is ...
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Interpreting output from lsmeans tukey test

I'm running post-hoc analyses on linear mixed models I ran for a dataset. I'm not totally sure how to interpret the output from lsmeans which is as follows: ...
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6 views

How do I manually calculate post-hoc tests of independence between all cells using output from SPSS complex systems module?

I'm trying to run post-hoc tests of independence between all cells using a data set that I need to run the complex samples module in SPSS. How do I use this output that includes population proportion ...
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22 views

How to discriminate among different post hoc friedman tests

I had to carry out several Friedman test comparing different yields. I also wanted to conduct a Post-hoc test to distinguish among different systems. I used the R function ...
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33 views

Post-hoc tests in mixed model using lsmeans and glht

I have a mixed model with two fixed factors (Insecte and temperature) with two random factors (bloc and date) nested in the temperature treatment. I also include interactions between the fixed factor ...
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17 views

What post hoc test should I run for a significant interaction in a two-way unbalanced ANOVA?

I have data with two factors (Category and Treatment) and each factor has two levels (A and ...
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28 views

ANOVA with Zero Variance

I have four sites. I would like to run ANOVA with Tukey's HSD post hoc test to show that an average hydrological variable (in this case peak runoff rate) is different across the sites. My issue is ...
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Interpretation of post hoc chi square test results

I have a $2\times 3$ table cross-tabulation. I've done a post-hoc test using SPSS but I don't know how to interpret the results. This is the output:
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Appropriate test for two test groups, one control group and binary outcome

I have the following problem: We send our Clients an email and offer them some new product. Let's say we want to test 2 email designs. Additionally, we need a control group, since some of the clients ...
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18 views

Conover and Nemenyi post hoc give different results

Using the Wine tasting data set as provided http://www.r-statistics.com/2010/02/post-hoc-analysis-for-friedmans-test-r-code i did Conover and Nemenyi post-hoc tests. They though give different ...
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Post-hoc tests linear mixed model lsmeans error [migrated]

I have a question about running post hoc tests on linear mixed models: I am running a linear mixed model in lme4 with 3 groups, 5 snakes per group, each group at a ...
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21 views

Calculation of pooled variance for mixed effect ANOVA

I have an experiment with 1 within-subject factor, 1 between subject factor and additional factor of blocking (measurements were done in several separated blocks). I have used GLM module of my ...
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14 views

How to do a post hoc test on a linear model with interaction?

I am new and I don't have much experience with R. That's why all the previous posts about this topic seem to be too complicated for me to apply for my case. I have ...
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27 views

2x2 anova as post hoc test following a 2x3 anova

I did a 3x2 anova - my data looks like in the figure below I get significant main effects and a significant (3x2) interaction. I now want to test the interaction between the blue and green bars. So ...
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18 views

Post-hoc tests after within-between Two-Way ANOVA

I'm new here! I have run an experiment with two groups randomized to different experimental conditions (A and B), where an outcome parameter was measured at four time points (1h,2h,3h and 4h) I ran ...
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14 views

R: Dunnett's test gives z and t value

I am using R for statistical analysis of my data. For some experiments I have to construct a linear mixed effect model using the lmer function from the lme4 package. For other experiments an ANCOVA ...
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38 views

R: Confusion about research question using GLM

I have a dataset with 3 colonies (A, B and C, see below). Each colony is divided into 2 treatments: control and DWV. I use a GLM to test wether there is a difference of the life expectancy ...
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26 views

Post hoc test (lsm) gives unverifiable t and p values for my lmer model

I have a model of the following structure: lme4::lmer(formula = signal ~ factorA + factorB + factor C + (1 | subj), data = s) and find a significant main ...
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30 views

Complex Factorial Manova in R/SPSS

Hello I have been struggling for many days with this problem. The situation and data set are following. The data set comes from an experiment that asked subjects (ID) to compare several CVs on ...
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66 views

Post-hoc test for lmer

I am running mixed models using lmer, and am having trouble running a post-hoc test to look at the significance between variables. The first 5 rows of my dataset (out of 119) looks like this: ...
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Is merging two factors (one between and the other within) into one for the friedman test a valid strategy?

Accoding to what I have read so far, there is no straightforward way to perform a 2-way non parametric mixed design, except permutation tests - which doesn't solve my problem (i.e. I cannot find a ...
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Analyzing repeated measures experiment with multiple treatment groups and multiple measures

I am doing a study to evaluate the effect of two dietary supplements on body composition. Literature suggests that Treatment 1 (Dietary Supplement 1) affects body composition with some side effects ...
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Post Hoc Test of interaction factor in binomial glmm with proportions

I've performed a binomial glmm, because my data are proportions of a species in a sample of +/- 100 Individuals. I test the interaction of two factors and use car::Anova to get the p-values. My ...
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Kruskal-Wallis test + Nemenyi post-hoc test: further multiple hypothesis correction needed?

I have used a Kruskal-Wallis test in a one-factorial design with samples that do not meet the assumptions for one-way ANOVA. To do this I have used the function ...
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Low correlation coefficient, low p-value. Is there an alternative/supporting analysis?

I have ran a series of (Spearman) correlation analyses. The resulting statistics result in low correlation coefficients (i.e. <0.01) and low p-values (indicating significance). Is there post hoc, ...
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What test to use post hoc?

I have several scenarios in which I would like to do post hoc tests, but I am unsure of what tests to do. These are two way anovas with some of the interactions as significant and some of the main ...
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21 views

posthoc tests on a 3-way anova with trimmed means

I am performing a 2-way robust anova using the WRS2 package, t2way function with trimmed means and mcp2tm function for posthoc comparisons. The 2 way design is looking at the effects of temperature ...
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31 views

Post hocs tests after a two-way ANOVA (randomized complete block)

I ran a two-way ANOVA on my data : fixed factor of 8 df ramdom factor of 14 df My random factor are the blocks and my blocks have only one sample and I therefore didn't need my data to be normal. ...
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25 views

Pairwise post-hoc test for 60 factor levels with multcomp's glht()

I am a molecular biologist, and i have tried 60 different PCR-Primers (for the record, only the forward primer was changed), and i want to compute if the selection of the forward primer has impact on ...
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64 views

Trying to choose the right post-hoc analysis for my unbalanced dataset

I encountered some problems with how to analyze my unequal design data set. The number of observations was influenced by survival rate of seedlings in tree nursery, where different concentrations of ...
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429 views

Friedman's test is very significant, but its post-hoc comparisons (SPSS) are not significant

I ran non-parametric Friedman's test for my data in the SPSS 22 and significantly rejected the null. That would mean that among the $k$ paired samples (3 in my case) there should be detected at least ...
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Pairwise significance tests with highly variable responses and small sample sizes

Please consider this experimental result of biological cell counts on differently treated areas: ...
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104 views

Welch's one-way ANOVA vs other solutions for unequal sample sizes

I want to make a one-way ANOVA with three groups of data (inflow bays, non-inflow bays and main reservoir) on methane emission. After transformation each sample group is normally distributed and a ...
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151 views

How to perform ANOVA followed by a post-hoc for model comparison?

My data is the measurement of 4 type of samples with three different methods where I want to see the interaction and main effect, compare them from each other. The data look like as follows: ...
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Sm.ancova statistics in R Question

New to R and sm.ancova. I have a covariate (soil moisture (WC)), dependent variable (Height) and group (Treatment). I have 3 treatment groups (Burned (3),clipped (2) and control (1). I decided to use ...
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1answer
83 views

Output of fixed effects summary in lmerTest in R and post-hoc tests

I'm doing a two-factor ANOVA using the lmerTest package. Each factor has multiple levels. When one (or more) of the effects are significant, I would like to do a ...
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13 views

Multiple Regression: 3 groups for IV, post-hoc equivalent?

I would like to test the following: DV - Brain volume IV - Participant Group (Patient with Mild Symptoms, Patient with Severe Symptoms, Controls) Covariates - Age, Gender, IQ I wish to use ...
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1answer
25 views

Same result for post-hoc test and probit regression

I am getting the exact same results for a probit regression and post-hoc tests (simultaneous tests for linear hypotheses) - is this because I have used a dummy variable in the probit model and so it ...
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90 views

Simultaneous tests for general linear hypothesis question

I have run a probit regression and am now trying to run post-hoc tests. I am trying to compare differences between a 3 level factor variable. I am confused about the difference between running a ...
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1answer
84 views

post-hoc test for betareg model R

I'm currently analyzing a dataset about quality of fodder. The data for e.g. crude protein content are given in %, I don't have absolute values. Because of the data structure (I don't give you the ...
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138 views

It's all in the family; but do we include the in-laws too?

Suppose I have an experiment with two or more factors. An overall ANOVA is constructed, and then we follow-up with two or more sets of post hoc tests, say multiple comparisons. My question is about ...
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2answers
593 views

lsmeans (R): Adjust for multiple comparisons with interaction terms

I have a lsmeans problem in R. I want to do a post-hoc analysis of an interaction, similar to examples provided in the lsmeans documentation. I am puzzled by the fact that the p-values are the same ...
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Post-Hoc Chi-Sq test - conclusions drawn from comparing individual categories

My question is very similar to this one: (Post hoc $\chi^2$ test with R), but I'm still confused, and tried to provide as much detail as possible. I have two categories of students: Domestic and ...
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78 views

Contrasts / Post Hoc Tests for three way repeated measures ANOVA

I have three factors A B and C with 2, 2 and 3 levels. A and C have significant main effects, B is not significant, interaction A*C is significant, the others are not. Now I want to know how to ...
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47 views

criteria for choosing a post-hoc tests

After eg. ANOVA there are several post-hoc tests out there (e.g. Tukey, Bonferroni, etc.) but what are the criteria for choosing one over the other? If one is more conservative, shouldn't we use it ...
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Methodological test for choosing 'worse' models that make 'better' (more realistic) predictions?

I've run 4 models (simple LM, quadratic model, GLMM, and GLMM with quadratic) to predict tree age (age) from tree diameter (D) for each of 42 species (SPEC). The diameter data has all been log ...
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Analysis of pairwise differences in species composition between sampling dates

I have six timepoints (months) with 60 samples each. I want to assess the species composition changes over time. For single taxa i used glht() (multcomp) with the ...
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Choosing to adjust or not after Kruskal-Wallis rejection

I have a series of data (4 numerical variables) and 4 categorical variables (with multiple factors each). I need to test for differences between various subsets based on the categorical variables. ...