Linked Questions
38 questions linked to/from Do we need a global test before post hoc tests?
4
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Use of "post-hoc" tests - do these require an ANOVA to be performed first? [duplicate]
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 ...
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1
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0
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Corrected multiple comparison: is the preceeding ANOVA necessary at all? [duplicate]
To compare multiple groups, one usually runs ANOVA. If ANOVA rejects the null hypothesis, one goes through the multiple comparisons.
The multiple comparisons are necessary to establish which group is ...
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2
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0
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Why do we conduct one-way ANOVA instead of jumping right into multiple comparisons if we have a simple, single main effect dataset? [duplicate]
This question is for simple data structure that involves one main effect only. I can definitely see ANOVA's usefulness in more complicated data containing multiple effects.
Aside from being a "...
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35
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4
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Can ANOVA be significant when none of the pairwise t-tests is?
Is it possible for one-way (with $N>2$ groups, or "levels") ANOVA to report a significant difference when none of the $N(N-1)/2$ pairwise t-tests does?
In this answer @whuber wrote:
It is ...
- 107k
23
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3
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How can I get a significant overall ANOVA but no significant pairwise differences with Tukey's procedure?
I performed with R an ANOVA and I got significant differences. However when checking which pairs were significantly different using the Tukey's procedure
I did not get any of them.
How can this be ...
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8
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3
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Non-significant results when running Kruskal-Wallis, significant results when running Dwass-Steel-Critchlow-Flinger pairwise comparisons
I am writing my Master's thesis on adult's performance on cognitive and linguistic measures. I have four age groups and am investigating if there is an age difference in the performance on summarized ...
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24
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1
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Why use ANOVA at all instead of jumping straight into post-hoc or planned comparisons tests?
Looking at a between-groups ANOVA situation, what do you get by actually doing such an ANOVA test first, and second do post-hoc (Bonferroni, Šidák, etc.) or planned comparisons tests? Why not skip the ...
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10
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3
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Relation between omnibus test and multiple comparison?
Wikipedia says
Methods which rely on an omnibus test before proceeding to
multiple comparisons. Typically these methods require a significant ANOVA/Tukey's range test before proceeding to ...
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8
votes
4
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3k
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Strange result of post-hoc test
I have data for a test on three groups. The measured variable is ratio scaled. The R code is
g1a<-c(7, 3, 40)
g2a<-c(1,1,2)
g3a<-c(0,0,0)
Since the ...
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4
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4
answers
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Repeated measures ANOVA with significant interaction effect, but non-significant main effect
I am running a two-way repeated measures ANOVA (main effects: Time, Condition). The result is that the main effect of time is significant (P<0.05), the main effect of condition is not significant (...
4
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3
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Non-significant Kruskal-Wallis and significant post hoc tests
I have done this analysis where in Figure A-D. the Kruskal-Wallis global p-value is non-significant, but the p-value for pair CS and SCS in Figure A however is significant (at P<0.05). I read ...
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10
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3
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Is there a consensus on adjusting alpha for multiple contrasts if the main effect is significant?
After talking to a couple of statisticians, reading some book sections, internet articles, and forums like this, I am still unclear about multiplicity adjustments of post hoc tests and contrasts.
Let'...
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8
votes
2
answers
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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:
...
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12
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1
answer
5k
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What question does ANOVA answer?
I want to learn ANOVA. Before I start to learn how the algorithm works (what calculations have to be done) and why it works, I first would like to know what problem do we actually solve with ANOVA, or ...
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ANOVA result indicated that there were sig. differences while Tukey post-hoc test revealed that there were no statistically sig. differences [duplicate]
I was conducted one-way ANOVA analysis to examone the level of knowledge shaorng among the employees based on there age differences. One-way ANOVA indicated that there were significant differences in ...
