"post-hoc" refers to analyses that are decided upon after the data has been collected, as opposed to "a priori".
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1answer
52 views
Post-hoc for 2x2 mixed design ANOVA using SPSS
I am analysing an experiment run with 20 participants using a 2x2 mixed design ANOVA. The experiment has
one within subjects variable A with two levels (a1, a2)
one between subjects variable B with ...
2
votes
1answer
44 views
How can I perform post-hoc tests to the ANOVA performed during K means clustering?
If I have highly dimensional data and perform k means clustering, I can end up with clusters that differ more on some axes than others.
SPSS provides the option to return an ANOVA for each variable, ...
2
votes
1answer
59 views
Three-way repeated measures ANOVA - what to do next?
I ran a 4(A)x4(B)x2(C) ANOVA in SPSS.
I got significant main effects of A, B and C, and significant interaction effects of AxB and BxC.
I got no significant interaction effects of AxC and AxBxC.
My ...
2
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0answers
38 views
Measuring change of participation level in a population after a policy change
I would like to measure the change of a policy in a community, that is, check
whether there was a change after the new policy was applied. The old policy
required that people had to give away a right ...
1
vote
1answer
59 views
Why did I get significant difference result before using post-hoc test but I got an insignificant result after using post-hoc test?
I have done an one-way anova test for to compare among 4 groups. I did the homogeneity test for variance and the result showed the variance was not equal but there was a significant difference between ...
0
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1answer
306 views
Post Hoc test for between subject factor in a repeated measures ANOVA in R
I have done an experiment of how different animal species affect nutrient fluxes in sediments. I had a number of experimental units (sediment boxes) to which different animal species were added. I ...
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0answers
49 views
Post-hoc analysis when variable effect is non-significant
In a dataset with 3 related measurements for each case, I ran a Friedman test, and found no significant effect.
Is it appropriate to now run (and report) pairwise tests, as I had planned initially?
...
0
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0answers
261 views
Calculating Tukey HSD following a repeated measures ANOVA
I was wondering how to calculate Tukey's HSD to follow up a three-way repeated measures ANOVA by hand. I tried to infer how to do it by modifying what I would do in a between subject ANOVA, but I'm ...
1
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1answer
230 views
Comparing groups at different time points within repeated measures study using SPSS
I have done a RCT (randomized control trial) of an intervention (which is of 6 week duration) versus control. The outcome measure (an exercise test) has been tested pre-intervention (Pre), immediately ...
1
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1answer
293 views
Two questions about Bonferroni adjustment
I have two questions about Bonferroni adjustments:
1). Can one use the Bonferroni method to compare independent groups? The reason why I ask this is it seems that many examples I've encountered ...
0
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1answer
93 views
Between group comparison for every level of within factor
If I use lme for mixed ANOVA as follow
...
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0answers
52 views
ANOVA post hoc with concerned about the sphericity
According to this post the best way to do post hoc analysis in ANOVA in R is t-test + ptukey. Because lme + glht "essentially assumes the sphericity assumption holds".
How are t-test + ptukey ...
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1answer
405 views
Post-hoc test after 2-factor repeated measures ANOVA in R?
I have problems finding a solution regarding how to run a post-hoc test (Tukey HSD) after a 2-factor (both within-subjects) repeated-measures ANOVA in R. For the ANOVA, I've used the aov -function:
...
3
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2answers
338 views
ANOVA results do not match post-hoc Tukey test, how to proceed?
There has been some discussion about why differences exist between factor significance after an ANOVA and no significance in the pairwise comparisons, and it has been very helpful. However, there is ...
0
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0answers
322 views
Chi-square is significant, post hoc test not, how to interpret?
I conducted a chi square test using crosstabs and found that there is a significant difference (p=0.020), but the post hoc showed that all the std residual were between -1.96 and 1.96. How to ...
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0answers
530 views
Pre-test, post-test multiple comparisons
This feels like it should be a very straightforward stats analysis but I'm struggling to find a solution.
I have a data set made up of pre- and post-test continuous data values taken from multiple ...
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0answers
495 views
SPSS Anova mixed between-within subjects. Which is the correct way to compare main effects?
I counducted a mixed model ANOVA with time as the within subjects variable (3 levels) and group as the between subjects variable (2 levels). All is significant (time, group, and timeXgroup).
I don't ...
2
votes
2answers
442 views
Anova repeated measures is significant, but all the multiple comparisons with Bonferroni correction are not?
I counducted a mixed model ANOVA with time as the within subjects variable (3 levels) and group as the between subjects variable (2 levels).
All is significant (time, group, and timeXgroup).
To test ...
5
votes
2answers
1k views
Post hoc test in a 2x3 mixed design ANOVA using SPSS?
I have two groups of 10 participants who were assessed three times during an experiment. To test for differences between groups and across the three assessments, I ran a 2x3 mixed design ANOVA with ...
0
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0answers
408 views
Multiple comparisons with the glht function in R gives strange results
As a follow-up to this question, I have the following data:
...
0
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1answer
78 views
Post hoc ANOVA following a significant ANOVA?
I am analyzing a data set using a one-way, within-subjects anova with 12 levels. Each of the levels represents a unique trial type in a reaction time experiment. However, the trials can be reasonably ...
1
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1answer
171 views
What can I conclude from the following one way ANOVA result?
I used a one-way ANOVA to test if importance levels of attributes have changed over the years (Data comes from a survey of consumers) with the following results (Mean ratings):
...
3
votes
1answer
489 views
Using lme to analyse a complete randomized block design with repeated measures: Is my model correct?
I've got a completely randomized block design with three treatments and four replications. Biodiversity was measured in four successive years.
I figured that a mixed model with repeated measures as ...
0
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0answers
411 views
pairwise t test or Tukey's test?
I have conducted an experiment with one group of subjects (n=14). I have two within-subjects factors and one dependent variable (called Error). The factor "Type" has 2 levels (Baseline, Operant); the ...
6
votes
1answer
534 views
Post hoc test of adjusted means (after ANCOVA)
When doing ANCOVAs, software usually gives both unadjusted means as well as adjusted means. However, the post hoc tests for most statistical programs are limited to unadjusted means. Yet, sometimes, ...
3
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0answers
729 views
Non-significant group effect, but LSD post hoc is significant. Why?
I am performing repeated ANOVAs in SPSS and came across something I don't understand.
Basically, the main effect of group (I have three groups) is not significant (p = .062), but the LSD post hoc ...
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1answer
627 views
Does the Tukey HSD test correct for multiple comparisons?
After performing an ANOVA and then doing post hoc tests with a Tukey HSD test is it still necessary to correct for multiple pairwise comparisons or is that done already?
3
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0answers
159 views
What are the possible multiple comparison methods for paired data?
I have been working with simulations, among them scheduling simulations. Each simulation chooses the number of steps, the arrival rate of new jobs and the duration of each step for each job. Thus, ...
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1answer
430 views
Testing for moderation with continuous vs. categorical moderators
I am testing an interaction effect where X and Y are continuous variable and M (Moderator) is a categorical variable (effects coding +1, -1).
I have no clue about how to do a post-hoc probing of ...
1
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0answers
422 views
Difference between MANOVA “post-hoc” tests of between subjects effects and between subjects one-way ANOVA?
When I run a 2x4x5x6 (Sex*AgeGroup*HighestDegree*Ethnicity) MANOVA (with 20 dependent variables) in SPSS, it presents tests of between subjects effects for each of the IVs and their interactions after ...
7
votes
2answers
2k views
How to interpret a post hoc Tukey's test?
I did a one-way ANOVA followed by a Tukey's test to compare the means of different treatments.
Let's say the treatments are A, B and C.
The table of multiple comparisons tells me there is a ...
1
vote
1answer
251 views
Post-hoc analysis on Friedman's test
I am using a Friedman's test with post-hoc analysis. I am using the function friedman.test.with.post.hoc available for R software.
Lets say we have 6 wines and we ...
5
votes
2answers
5k views
How to obtain the results of a Tukey HSD post-hoc test in a table showing grouped pairs?
I would love to perform a TukeyHSD post-hoc test after my two-way Anova with R, obtaining a table containing the sorted pairs grouped by significant difference. (Sorry about the wording, I'm still new ...
3
votes
1answer
341 views
Use of “post-hoc” tests - do these require an ANOVA to be performed first?
I would like to compare multiple means using a method such as an ANOVA. This would have to be followed up with either Scheffe's test or the Games-Howell post-hoc method (my data is non-normal - to ...
3
votes
2answers
2k views
If only a two-way ANOVA main effect is significant, what is the appropriate follow-up?
What (with justification) is a valid post-hoc for a two-way ANOVA main effect, if no interaction is present?
Example two-way fixed effect ANOVA:
...
5
votes
2answers
2k views
What is a valid post-hoc analysis for a three-way repeated measures ANOVA?
I've performed a three-way repeated measures ANOVA; what post-hoc analyses are valid?
This is a fully balanced design (2x2x2) with one of the factors having a within-subjects repeated measure. I'm ...
0
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0answers
402 views
Three-way Repeated Measures ANOVA [closed]
I've posted this question (along with example code and output) at http://www.reddit.com/r/rstats/comments/tglt8/threeway_repeated_measures_anova/
Is this a valid ANOVA model, and are sphericity tests ...
2
votes
0answers
65 views
Weighting a control group
In reviewing some market research, I came across a study which decided to weight the results/outcomes of the control group so the distribution of participants in the control sub-groups (0,1,2,3,4,5 - ...
0
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0answers
543 views
Using a post-hoc test after creating an LME model
Is a post-hoc test necessary when using an LME test for repeated measures?
Assume that, in R, a summary of the LME model (lmemodel) would show significant levels ...
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1answer
87 views
How to interpret the T-depiction of multiple comparisons used in R's multcompView package?
R's multcompView package offers a seemingly useful set of tools to visualize the results of multiple comparisons, e.g. Tukey HSD analysis, including boxplots and 'letters' to identify ...
1
vote
1answer
348 views
What post-hoc test can be used on data with missing values?
I have run 13 data-stream classification approaches on 8 different datasets, giving a 8x13 result table. I was hoping to use the Friedman test to test for a significant difference between the ...
2
votes
0answers
1k views
Difference between post-hoc test after Kruskal-Wallis and Bonferroni corrected Mann-Whitney tests
I have some non Gaussian distributed variable and I need to check if there are significant differences between the values of this variable in 5 different groups. I have performed Kruskal-Wallis one ...
4
votes
3answers
1k views
How to do post-hoc tests with logistic regression?
I looked at whether participants recycled after being subjected to a given message. There were three groups: a Control group, group A, and group B.
Since my dependent measure was dichotomous ...
2
votes
2answers
66 views
Are benchmarking and post-stratification equivalent?
Does "benchmarking" and "post-stratification" describe exactly the same process? The Wikipedia article on Statistical Benchmarking claims it is; however, the article on Sampling also mentions ...
6
votes
1answer
2k views
How to perform post-hoc comparison on interaction term with mixed-effects model?
I’m working on a data set in order to evaluate the impact of drying on sediment microbial activities. The objective is to determine if the impact of drying varies among sediment types and/or depth ...
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0answers
504 views
Non-parametric test for repeated measures and post-hoc single comparisons in R?
Some attribute x of 17 individuals was recorded repeatedly on 6 time points using a Likert scale with 7 distractors. Which statistical test(s) can I apply to check whether the changes along the 6 time ...
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0answers
1k views
Why does one get a 0.000 Mann-Whitney U value (not p-value) etc.?
1) Is it okay to run a Mann-Whitney U test on unequal sample sizes i.e. two groups (N=11, N=12)or is there an alternative test?
2) What does it mean when one obtains a zero value for a Mann-Whitney U ...
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vote
3answers
3k views
Non-parametric test for unequal samples with subsequent post-hoc analysis?
Is it okay to perform a Kruskal-Wallis on four unequal samples? Further to this, is there a subsequent pair-wise post-hoc suitable for two unequal sample sizes?
6
votes
3answers
3k views
Sidak or Bonferroni?
I am using a generalized linear model in SPSS to look at the differences in average number of caterpillars (non-normal, using Tweedie distribution) on 16 different species of plants.
I want to run ...
3
votes
2answers
463 views
Best method to visualize large interaction between two factors
In a simple experiment I asked participants to make acceptability judgements (9-point Likert scale) when they observed different animated virtual characters. I have two factors: character (7 levels) ...
