Questions tagged [bonferroni]

Bonferroni refers to a method of adjustment for multiple comparisons in which the p value is divided by the number of tests. It is more conservative than many other such methods.

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MANOVA contrast results p-value in SPSS - Bonferroni correction required?

I am running a MANOVA with 2 IVs(2*3) and 4 DVs. I want to test the effect of the 3-level IV using a Helmert contrast: to compare if level 1 significantly differs from the mean of levels 2 and 3, as ...
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What counts as a comparison?

Say we have a test in which we are comparing many variables to a dependent variable, using different methods. Say ttest, chi2 and then finally a multiple regression on parts of the data. Would we ...
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How to conduct Holm's procedure for two-sided Wilcoxon signed rank test when conducting pairwise comparisons for multiple classifiers?

I am trying to compare the accuracies of m classifiers on multiple datasets. Following the suggestion of the JMLR'16 paper "Should We Really Use Post-Hoc Tests Based on Mean-Ranks?", I have decided to ...
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conducting a multilevel model with a continuous variable and categorical variable in r (+ post hoc)

I conducted a study in which I presented three types/blocks of visual stimuli (neutral stimuli in baseline, negative stimuli, neutral stimuli following negative stimuli). To examine the relationship ...
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A one-way ANOVA for multiple comparison

Cheng, H., & Liu, S. (2019). Haptic Force Guided Sound Synthesis in Multisensory Virtual Reality (VR) Simulation for Rigid-Fluid Interaction. In 2019 IEEE Conference on Virtual Reality and 3D User ...
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Multiple comparison adjustment with multiple outcomes, measured over time

I am trying to work out the most appropriate way to adjust for multiple comparisons. I have 20 biomarkers which have been measured at 4 timepoints (baseline & three unevenly spaced follow-ups). I ...
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Does “uniformly more powerful” also mean the same or fewer type I errors?

Does a "uniformly most powerful" (UMP) test also imply that it will make the same or fewer type I errors? Specifically, is there ever a (statistical, not convenience) reason to use a simple Bonferroni ...
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Significant main effect but no interaction which post hoc test to do?

I have an experiment looking at the effect of rearing condition on development of the number of neural networks (ensembles) in mice. I therefore have two factors (Age 3, 5, 7 dpf) and Rearing ...
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Multiple testing on the same dataset

I have a dataset with n = 76 independent test subjects (rows) and 3 dependent variables (columns) (which are related as a process taking place over time). For the example below I will assume I have ...
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Alternative for Bonferroni correction for two groups using SPSS

I have two (2) groups of children that have been tested on the same series of tests. Trying to check a series of hypotheses, I compare the performance of both groups on these tests, using one-way ...
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I have performed three likelihood ratio tests on a factor in R. Do i need to adjust the p values?

I am a student doing a thesis for zoology. I am looking at how factors like season (winter/summer), fencing (inside fence/outside fence), and the interaction between season and fencing affects ...
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When do we “stop” using multiple correction techniques?

I understand when performing a simple t-test, we typically control the type -1 error rate at $\alpha = .05$. This signifies that if the null hypothesis holds, the data will "incorrectly" reject the ...
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Same value P-Values - Holm-Bonferroni

When using a Holm-Bonferroni adjustment method or the like, how to you treat multiple p-values of the same value when ranking? For instance, I have the unadjusted p-values: ...
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Do I need a Bonferroni correction on a 2x2 chi-squared analysis?

I'm really hoping someone here can help. I have performed a chi-square test of independence, looking at men/women and early/late drop out from therapy. I have a p-value of 0.047. Do I need to do any ...
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How to adjust P-Value for Multiple Tests

I'm not sure if this is answered or not because there's a lot of these questions and the ones I looked at didn't answer this. If I were to say, have five independent variables of interest and one ...
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Considering pre-tests in family-wise error correction doing an ANOVA

When I do multiple tests on a dataset, I need to correct for the family-wise error (e.g. using Bonferroni method when performing multiple pairwise t-tests). If I do an ANOVA, I need to make sure that ...
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Apply Fisher's exact test on multiple class

I am testing the presence of viruses within samples, which are matched 'normal', 'cancer' and 'metastasis'. I am testing the presence of viruses at species, family and order level. For instance, I ...
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Is it necessary to adjust for multiple comparisons (e.g. Bonferroni) when using continuous interaction terms (e.g. age)?

I am interested in analyzing how the effect of a dichotomous variable on a dichotomous outcome changes by age. In reading this how-to article from UCLA's Institute for Digital Research & Education-...
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Adjusting p-values for multiple comparisons: if Bonferroni adjustment = α/??, what's my?

I'm testing the effect of two different informational treatments on individuals' attitudes towards certain policies. I know I need to adjust my p-values for multiple comparisons. Using the ...
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207 views

Confidence intervals and bonferroni correction

Currently I'm thinking about using confidence intervals to compare the difference in means between a few groups. However, if I understand correctly I need to use the Bonferroni correction if I test ...
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What is the right Bonferroni adjustment?

I am trying to test a hypothesis for my Masters Thesis. There are 3 conditions (I will name them X, Y, Z), in each of which the data isn't normally distributed, and measures the improvement for each ...
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Multivariate post-hoc tests and multiple comparisons

My research group is currently working on a medical imaging project in which we are studying brain perfusion in patients affected and unaffected by a particular type of injury using a technique called ...
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Fisher's Exact Test and bonferroni correction in r

I try to find out whether there are significant differences in Categories between several groups. My data looks like: ...
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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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correct for multiple testing on correlated data with NaNs

First of all, I'm not a statistics expert, so I hope I can describe all relevant details of my problem: I'm working with a dataset consisting of subject age (1st column), 13 ordinal scaled parameters ...
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Need of p-value adjustment when analyzing all possible pairs of factor levels in linear model

I have a nominal (not ordinal) variable with $K$ levels (these are actualy some groups of patients) and I run linear model in which: this nominal variable is one of IV's (others are age, sex and so ...
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2 sample t-test with multiple tasks Bonferroni correction?

Let's say I have a between-subject design with 2 conditions (male, female) and I want to test if: males solve math tasks faster than females. males do less errors when solving the task I am ...
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Using bonferroni with t.tests & regression

I have theoretical knowledge of why we should use bonferroni; however, unfortunately not how. I am conducting multiple t.tests, sometimes within the main data (number of t.tests = 5, number of main ...
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3 way ANOVA / Duncan test

I am runnig 3 way ANOVA between: specie * organ * treatment in Sucrose acumulation. There is interaction between organ*treatment, but no interaction between specie and organ or treatment. Should I ...
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Non replicated vs replicated field trial

I need to conduct a pesticide efficacy trial on avocados. I have been asked to describe two different trial approaches: replicated and non replicated. I have drawn the two trial design options. ...
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Bonferroni for Wilcoxon signed rank?

I conducted a survey that asked participants to rate their level of agreement on a 5 point Likert scale with nine items (1=strongly agree, 5=strongly disagree). Hence, a mean score of 3 would mean ...
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What is function of Holm-Bonferroni? [duplicate]

I am confused about Holm-Bonferroni. Suppose we want to compare age of female and male students using t tset. We also want to compare length of arm and elbow between male and female students. I ...
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Correcting for multiple 2-way anova testings (each IV only has two levels)

I have two independent variables, both of them only have 2 levels (Story type: Homosexual vs. Heterosexual, and Stereotype: High vs. Low). I run three two-way ANOVAS, to test the IVs' effects on ...
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Defining my number of multiple comparisons for a Bonferroni correction

I'm a grad student doing analysis on a survey. One of the things I want to note from this study is whether demographic factors of respondents are connected to the answers they gave (how do men or ...
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Multiple comparisons correction for dependent comparisons

In this blog post the authors discuss simultaneously estimating quantiles, and constructing a simultaneous confidence envelope for the estimation which covers the whole quantile function. They do this ...
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Twenty samples should be the same. But How should I test that

I have a table derived from a group of polypeptides or proteins. Because they are proteins they are made up of 20 amino acids. Iff a group of proteins contains a random sample of amino acids then the ...
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Applying Bonferroni or Holm-Bonferroni correction to interaction effects and simple slopes

I am seeking to apply a correction to my exploratory analyses to account for familywise error. I am conducting moderated MRAs with 7 different moderators, 1 IV, and 1 DV. I am interested in ...
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Can Bayes factors be an alternative to multiple comparisons corrections?

I am currently using p-values and Bayes factors to interpret my results. I have multiple comparisons so was going to perform a Bonferroni correction, however I am hesistant due to its highly ...
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Bonferroni confidence region for shifted Laplace parameters

Consider the shifted Laplace distribution with the density: $$f(y)=\frac{\theta}{2}e^{-\theta|y-\mu|}\quad, \quad y\in \mathbb R$$ Using the Bonferroni method, construct a $100(1-\alpha)\%$ ...
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How to interpret a statistically signficant finding that becomes unsignificant after bonferroni correlation

I hypothesised I would find a main effect of X which I did (p=0.028), however, upon using the bonferroni correction my alpha dropped to 0.0125, making this result no longer significant. I found a ...
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Is it necessary to do a Bonferroni correction on a) exploratory analysis b) correlations or c) if there are 3 different dependent variables

My study is a 2x2 within design and I have a series of 8 hypotheses. These include one ANOVA , one t-test and 4 Pearson correlations. However, the ANOVA and 3 of the correlations include the same ...
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Compensate for multiple experiments or not

My last question let to some confusion about the source of my data, so I will do my best to explain the experiment from the beginning. It starts with a game (game theory), let’s say a cooperation ...
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Significant interaction in Mixed-design 2-way ANOVA. How to correct for multiple comparisons?

I have conducted a mixed-design two-way ANOVA (between subjects variable : 2 levels; within subjects variable : 8 levels). I have a significant main effect of between and within subject variables and ...
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Can and should you avoid implicit pretesting for differences in group means?

Suppose I have a population with four (or more) disjoint sub-populations which differ from one another by traitishness, the union of which is the whole population. I have an outcome measure on the ...
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108 views

Holm-Bonferroni correction with two interactions

I try to get a sense of the correct adjusted Holm-Bonferroni significance levels $\alpha$ when dealing with multiple interaction terms. To simplify, assume one has the following model: $$ y=\beta_0 + \...
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170 views

alpha value in Bonferroni corrected test

I ran some analysis with Bonferroni corrected test in R. Now my supervisor asked me what the value for alpha is for my analysis and since I haven't changed the default value it should be same as ...
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53 views

Correcting for multiple post hoc tests in factorial ANOVA

I have done a two-way repeated-measures ANOVA with factor A having 3 levels and factor B having 5 levels. I am doing post hoc comparisons between all 3 levels of factor A within each of the 5 levels ...
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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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FIsher's LSD test is appropriate for restricted mean comparisons

Suppose that we perform two way ANOVA with interactions, with factors $A$ and $B$ with three level each $A_{1},A_{2},A_{3}$ and $B_{1},B_{2},B_{3}$. We know that Fisher's LSD test is used for ...
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Repeated measures models multiple testing adjustment

Perhaps I am missing something obvious here, but I can't find an answer to this. Let's say we run 10 individual repeated measures models with factor(time) as fixed effect with 5 separate timepoints ...