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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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21 views

Differences between years in time series data

I have a multiyear time series dataset detailing the concentration of environmental contaminant over time. and I need to determine if there is a significant difference between the yearly means. In ...
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5 views

What test adapts to this situation

Hello im trying to use sigmaplot and do a one way ANOVA and a comparison to a control group this is to a problem of an enzimatic production by the same organism in prescence of a drug at diferent ...
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44 views

Why is one mean not significantly greater if every element is greater than the other group?

the mean of group C and every element in group C is greater than its row-wise peers. Why is the Tukey comparison giving insignificant P-values? ...
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ANOVA: life after rejecting the null hypothesis

I have multiple groups of data (20+ groups) and test the null hypothesis that they have the same mean. How do I proceed after the null hypothesis is rejected? What is the standard method for selecting ...
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111 views

Does R use Tukey or Tukey-Kramer test corrected for unequal sample size and does it use the multivariate t distribution?

Does R use the classic Tukey HSD test for balanced data or corrects for unbalanced ones with the Tukey-Kramer approach? I mean the stats::TukeyHSD(). I found, that the Dunnet procedure uses ...
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61 views

How is the standard error used in calculating a Tukey HSD defined and calculated?

I am looking at someone else’s published data where they report treatment means and then a single standard error value across treatment means. I want to know if certain treatments are significantly ...
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40 views

How do I report results from a Tukey post hoc analysis?

I examined all possible comparisons in the Tukey test (here is the chart - sorry it's a little unclear) https://scontent.fybz2-1.fna.fbcdn.net/v/t1.15752-9/...
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1answer
15 views

Default multiple comparison correction in TukeyHSD in R? [closed]

Does anyone know what the default method is for adjusting for multiple comparisons is in the TukeyHSD function? (e.g. BH, Bonferroni, etc.)
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21 views

p-value calculated using ptukey() does not agree with p-value obtained from TukeyHSD()

I have the following toy dataset group1=c(1,2,3) group2=c(5,6,7) group3=c(2,4,6) ex1=rbind(group1,group2,group3) ex1=melt(ex1) I build an ANOVA model, solve it, ...
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51 views

emmeans/multcomp in R vs multcompare in Matlab

I am analyzing a dataset with one within variable (Xw1) and one between variable Xb1. The within variable (...
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38 views

How can I compute a confidence interval on Cohen's d derived from a Tukey HSD contrast?

Question Background Consider for example that I have some data arrayed as a 1-way (Group: A, B, C, D) between groups ANOVA. Consider further that I am interested in all possible pairwise contrasts ...
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Interpreting Tukey HSD grouping results with one item interacting in multiple pairwise comparisons

I'm looking for help on how I should go about interpreting/concluding the outcome of my post-hoc Tukey HSD analyses. I'm trying to discern if the 12 operational efficiency groups I'm reviewing for a ...
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1answer
179 views

Calculate Cohen's d for pairwise tukey tests in a 1-way ANOVA

I have the following dilemma: Design: 1 (Group: Patient vs. Control_1 vs. Control_2) between-factors design arrayed as a 1-way ANOVA Analysis: Following a main effect of group perform I perform all ...
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13 views

Understanding the k-folds data split requirements for a Tukey's HSD test

I have 2 machine learning methods A and B, and a set of data with 100 examples. I want to evaluate A and B with a 10-fold validation, so I train A and B with 9 sets of 10 examples, and score A and B ...
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1answer
33 views

Are there any situations where ANOVA performs better/is more useful than Tukey's HSD?

In statistics this week we are learning about ANOVA and Tukey's HSD. If ANOVA only tells you whether the differences in the means of the groups are significant, but Tukey's HSD gives you the ...
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23 views

Multiple comparisons from means and standard deviations

I am attempting to do a statistical comparison of the mean concentrations of certain ingredients between different varieties of a product, based on summary data. An example table depicting the type ...
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2answers
115 views

How to select the best variant from an A/B/C test?

Suppose I've run an A/B/C experiment (same as A/B but with 3 groups instead of 2) and gathered the following data for number of participants in each group and number of desired actions in each group (...
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27 views

Post Hoc Tests with a lm model where model assumptions are violated

I have the following data set: dependent variable is carbon levels in manure. Independent varibale is the month that the manure was collected in (12 level factor). I want to test if there is a ...
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For microbiome data, is there a way to stratify within Tukey HSD?

I have Shannon diversity metrics for samples that are repeated measures collected over time with different genotypes and I would like to stratify the Tukey by the collection time. ...
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1answer
53 views

Using pairwise comparision on gls object [closed]

I have one factor (tree genotype) and I analyse its influence on soil content. I used gls to aply weights on my data because it's a better fitted model. Here is an exemple of my data with one ...
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56 views

Post hoc for Levene test

I have a problem regarding my data analysis. One of my hypothesis is basically that my groups will differ in terms of spread of the scores, indicating that there would be a difference in extremity ...
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1answer
49 views

Splitting groups for statistical comparisons

I have a question that I cannot answer based in my biological background. I conducted one experiment with 5 replicates and 4 treatments. There were two goals: the first goal was to elucidate if our ...
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1answer
11 views

Tukey Kramer and the reduction of type one error

I hope everyone is doing well. I understand that the Tukey Kramer reduces the chance of getting a type 1 error by using a pooled variance. That pooled variance then gives you a lower standard error ...
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1answer
163 views

TukeyHSD p-value is less than t-test p-value

I have some data where when I do t.test for a specific pair of groups, the p-value is (barely) higher than when I do TukeyHSD ...
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1answer
727 views

How to calculate Tukey-adjusted p-values for emmeans pairwise comparisons?

I would like to calculate Tukey-adjusted p-values for emmeans pairwise comparisons. I know that these can be obtained directly with functions like pairs() and CLD(). However, when there are three ...
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2answers
44 views

Multiple comparison problem

If I conduct 19 tests (e.g. 19 pairwise comparisons of treatment means in an experiment), what is the probability that I will find at least one P value < 0.05 due to chance alone? With number of ...
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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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375 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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56 views

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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21 views

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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1answer
175 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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2answers
601 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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371 views

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
57 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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1answer
267 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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524 views

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
84 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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34 views

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
325 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
326 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
209 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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0answers
189 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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0answers
1k 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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246 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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57 views

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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1answer
83 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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1answer
724 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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1answer
160 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
243 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
923 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 ...