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Questions tagged [tukey-hsd]

Tukeys Honest Significant Difference (HSD) is a multiple comparison method based on the studentized range distribution.

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PostHoc Tests after two way anova in R

I have a data table with 2 explanatory variables: Noise, with 2 levels ("Exposed", "Unexposed") Voltage, with 9 levels The dependent variable is Delta Cm So, after checking Normality and variance ...
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1) Am i right in conducting an ANOVA 2) no p value because of lack of results

Im unsure whether I should conduct a two way ANOVA as GLM on minitab 17. Got seven mutant plants (with different knockout genes, including the wildtype and lines incase a knockout didnt occur). I'm ...
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25 views

How to report the results of the Tukey HSD syntactically/formally correct?

For the ANOVA i use this form: F(2, 1279) = 6.15, p = .002, w^2 = .010. Let's say i did some post hoc testing and the result is this: ...
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How to properly evalulate data from multiple Likert scale surveys for multiple groups

A questionnaire was sent at several times T(1,2,3,4) to 3 groups G(A,B,C). Now, for each question i would like to find out whether or not: in the course of time the results have changed the results ...
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How to interpret Tukey-post hoc results for two explanatory variables in a multiple model?

I've fitted a multiple linear model with three explanatory variables. No interactions were found but the effect of two of them (Time and Salt concentration) were found to be statistically significant (...
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29 views

Anova of a mixed effect model (lmr) shows no significant interaction while tukey (emmeans) does?

I have run a linear mixed-effects model using lmer package. I'm using year sampled (1990s or 2017), field(1967 or 1984), and treatment (open or closed) to determine differences in native herbaceous ...
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33 views

Interpreting a Tukey - Kramer Confidence Interval Plot

In order to see if any statistically significant differences in the means of 4 particular diets exist, a post-hoc test is conducted i.e. Tukey – Kramer. Could someone please explain to me the plot ...
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Using pairwise comparison on gls object with heterogeneity of variances?

I'm comparing total yield from fields under 5 different treatments. As you can see, the variance differed between the treatments (diagnostics from lm() fit): So I ...
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1answer
44 views

How to conclude that all group means are different?

Suppose I have groups $G_1$ to $G_n$ with sample means of the variable of interest $m_1$ to $m_n$ respectively and sample variances $s_1^2$ to $s_n^2$. What tests can I perform to conclude that the ...
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62 views

What post-hoc analysis should I use following a two-way ANCOVA with factor, integer and numeric variables?

I ran a two-way ANCOVA on the data below, in r-studio, to determine whether pupal weights Pupal.wt were affected by caterpillars' diet ...
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Pairwise comparisons after ANOVA with Tukey and Bonferroni methods in r

The built-in functions TukeyHSD and LSD.test from R perform pairwise comparisons. In order to maintain the type I error, the significance level $0.05$ is divided by the number of comparisons $k$. Do ...
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1answer
80 views

How to show specific results in R using Tukey test?

I have a question about showing specific results in R. I am using a linear mixed model and checking the stats between each condition (adding 1, then adding 2, then adding 3...) in a repeated test, ...
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Simple GLM analysis on Springtail Community Dynamics: determining which variables affect Abundance

I'm looking at Springtail community analysis and want to see what, if any, affect Litter Type (LT), Site Type (ST), and Sampling Day (SD) have on springtail abundance. LT and ST both have 3 factors ...
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1answer
53 views

Adjusting p-values for multiple ANOVAs

I am performing multiple (around 40) multi-way ANOVAs on a dataset, one for each outcome variable. There are three factors involved: cohort, pre/post, and tissue type. For each outcome variable, I ...
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1answer
66 views

Which is right to perform a Tukey post hoc in R? [closed]

I know 3 ways to perform a Tukey post-hoc test in R and the results are a little different. Initially, I performed a two-way anova ...
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1answer
59 views

Tukey-Kramer or Nemenyi following Friedman

I previously asked a question here after discovering an option by MATLAB to run Tukey-Kramer for multiple comparison multcompare following Friedman test and many ...
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25 views

T-tests vs multiple comparison tests vs bonferroni in ANOVA?

I'm taking a course in experiment design and I'm having a hard time grasping the comparative usefulness of t-tests, multiple compariseon tests and bonferroni methods. I understand that in using ...
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57 views

What is the point in reporting the z statistic of a z-test?

In my field some authors report the z statistic of a z-test in a generalised linear model and others do not. Does reporting the z statistic serve any purpose if the p value of a z-test or of a post-...
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219 views

Two way ANOVA and post hoc test

I performed a two way ANOVA over a test set. My two nominal variables are treatment and clone. My outcome variable is area. ...
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93 views

ANOVA and tukey test on categorical variables

I have a data frame like the one below, I want to apply an anova test and tukey post hoc test analysis. ...
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A question about Tukey HSD test

Does Tukey comparison in glht/multcomp package in R refers to Tukey HSD test? Can I use the Tukey HSD test (for multiple comparisons) after applying the Robust technique (Such as Robust Anova, Robust ...
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53 views

How to state my model in R in words (linear mixed effect model, general linear hypothesis, Tukey, Benjamini Hochberg)

I have a dataset that has four treatment groups (AX, AY, BX, BY). I am trying to determine if there is a significant difference in a response variable (Length) between any of these four treatment ...
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269 views

Tukey HSD plot_simultaneous - how does it work?

I have performed a Tukey HSD in Python. I am not sure what values are plotted when using the .plot_simultaneous() command (see statsmodels documentation). The resulting plot is: I am wondering: how ...
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98 views

Are the results of my paired tests false positive?

I am dealing with a strange situation which I hope you can come up with a solution. I have 3 pared group(n=7 for each) which I tried to see if they are significantly difference and if so, in which ...
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1answer
97 views

How do I perform an ANCOVA ? (master thesis deadline) [closed]

My dataset consists of several morphological measurements for 5 island populations of a certain lizard species. I want to test for each population if there is a significant difference in the ...
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2answers
354 views

Post hoc test for Friedman test

I am running a Friedman test for my non-Gaussian data, on MATLAB. However, I am confused about the post hoc test to choose. Two concerns: (1) MATLAB's multcompare ...
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1answer
461 views

R Tukey HSD Anova: Anova significant, Tukey not? [duplicate]

i created a simple anova with three groups in R and get a significant Result. After that i do a Tukey HSD Test and now nothing is significant. How can that be? Pr(>F): 0.0316 Group | p adj 1 - 2 ...
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716 views

What are the (practical) differences between Tukey's HSD and the Dunn-Sidak correction procedures?

I have a data set with three groups, one of which is a control and the other two groups have been administered either a moderate or a high dose of a drug. The data are not normally or log-normally ...
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67 views

Tukey's alternatives!

I have 10 independent groups and I need to know which one is significantly different than others. I am planning to use One-way ANOVA then multi-comparison test. I used Tukey's test but it always ...
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2answers
221 views

Differing p-values car::Anova, anova & post hoc in logistic regression

I am currently working with a logistic model in R and I have a question regarding the p-values that I get from different types of tests. Since I have separation in my data (caused by X) I use the ...
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1answer
397 views

Which one to choose Type-I, Type-II, or Type-III ANOVA? [duplicate]

I don't understand what the difference is between TypeI and TypeIII? Since my background is not very mathematics, it's very difficult for me to understand this mathematical notation; Type I SS: SS(A) ...
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152 views

Power analysis for one way anova with post hoc Tukey?

I have an experiment in which I'm doing, among other things, a One way Anova with one dependent variable and 5 groups. After the ANOVA i'm doing Tukey's post hoc to test for differences between groups....
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Regression analysis strategy in r

Disclaimer: I'm a bit of a stats noob, sorry for the wall of text. Any help is very much appreciated. In my stats class, I've been tasked with examining data from A study comparing two methods of ...
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What contrast should I use to test this hypothesis?

I'm conducting an experiment for an undergraduate stats course where I see how water temperature affects the rate at which ice melts. My hypothesis is (obviously) that the rate at which ice melts ...
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104 views

Linear mixed-effect ANOVA and Tukey Honest Difference Test (Suitability and interpretation)

I am hoping to verify that I completed a statistical test appropriately. I am working with a dataset consisting of 59 cages that each had 35 organisms. Each cage was exposed to one of two diets (A or ...
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1answer
1k views

Why do planned comparisons and post-hoc tests differ?

I conducted a three-way independent ANOVA. I manipulated the sound of my stimulus to be 1: congruent (KON), 2: incongruent (INK) and 3: no sound at all (control condition). One of my planned ...
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1answer
104 views

Comparing different treatments using logistic regression

I have some data on testing different pesticides on insects. I have applied different concentrations and different pesticides (total 11 treatments) for 24 hours, and have 6 different data points. I'm ...
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1answer
64 views

Adjust for multiple comparisons in several mixed models

I am fitting several generalized mixed models with binomial family to model proportions data(dependent variable) and 3 factors.The data looks like this: Sample Day ligand Condition Conc1 Conc2 .... ...
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1answer
246 views

Interpreting ANOVA, Tukey, Linear Mixed-Effects Results

I am trying to follow the work of a scientist who compared two factors (A and B) each with two levels. The general output from R appears as follows: ...
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1answer
69 views

Why “Honestly” in Tukey's Honestly Significant Difference (HSD)?

Why is the word "Honestly" in "Tukey's Honestly Significant Difference"? It seems unusual. Most statistical procedures are developed with the intent to give an "honest" answer. Why is that word ...
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1answer
1k views

Post Hoc Pairwise Comparison of Interaction in Mixed Effects (lmer) Model

I have searched other posts and textbooks and found numerous variations of the pairwise comparisions for my mixed effects model using code from the multicomp ...
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3answers
73 views

Is this an example of a multiple comparisons problem?

I am conducting a comprehensive research determining the effect of 3 independent variables on the metabolic rate of an organism. However, the set-up of my data analysis leads me to believe that I ...
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1answer
1k views

Tukey with interaction and extracting letters in multcomp

I've seen similar questions posted elsewhere with no answer, so I thought I'd put this out into the CrossValidated universe. I am attempting to do a Tukey's post-hoc test on a model that has an ...
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1answer
78 views

Possible to have insignificance when two groups have non-overlapping 95% CI for Tukey test?

I am comparing three group means (95% CI), as following: A (n=248) B (n=1000) C (n=102) 1.3 (0.6-2.1) 3.9 (3.1-4.7) 2.5 (1.2-3.9) There ...
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29 views

how to find which row is significantly different

I have a data which looks like this ...
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1answer
299 views

One-way ANOVA, clustering levels using Tukey Kramer HSD

Suppose I am doing a one-way fixed effect ANOVA on an unbalanced data set. Let the number of levels of the one way factor be "a". Suppose the omnibus null hypothesis is rejected. So I do a post hoc ...
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103 views

Should I use post-hoc tukey HSD or some other test for pairwise comparisons of a factor on a zero-inflated negative binomial mixed model (ZINB)?

I ran a zero-inflated negative binomial mixed model (ZINB) and now have a statistically significant factor (recording type, either NOCA, BCCH, or Human). To assess the differences between these three ...
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1answer
2k views

Paired t-test and Tukey post hoc

I am running a repeated measures anova. Once I get significant p values, I run paired t-tests and I also apply Tukey post hoc. The fact is that I get lower p values with Tukey than with paired t-...
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Compute the power of Tukey's Honest Significance Difference (or cognates)?

I've got a simple computational model I can run experiments with. Experiments are "free" but I don't want to run it more times than necessary because it still takes time. All the simulation use the ...
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1answer
71 views

How to do Post hoc tests

I have conducted an experiment with 12 conditions (1 baseline). One of the response variables is binary, others 7 point Likert scale. I want to test all other conditions against the baseline (11 ...