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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30 views

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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24 views

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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39 views

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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69 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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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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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 ...
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Bonferroni interval - quick example calculation

Problem statement: Calculate the Bonferroni interval for any pair of means $\bar{y}_{.j},\bar{y}_{.k}$ with $I$=10 groups with equal sample size 30 in each group. Write this as a multiple of $s$. ...
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evaluate relationship between 1 independent variable and multiple dependent variables.

To evaluate the relationship between variables coefficient of correlation and coefficient of determination obtained from regression are used. But what is the procedure if I have 1 Independent variable ...
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multiple comparison with controls - kruskall wallis or mann whitney + bonferroni

I have a test group and two control groups. I would like to compare: test vs control group 1 test vs control group 2 and I don't need the result from control group 1 vs group 2. Therefore, in this ...
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196 views

Bonferroni-type corrections and Fisher Method Meta-analysis

I'm not an expert on the field, but I need to know more about how to combined multiple significance test p-values after a two sample Kolmogorov Smirnov (KS)test on two distributions. But I have two ...
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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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Bonferroni correction and discussion of the results

In a study in which I analyze several biomarkers through logistic and linear regressions, should I discuss in the discussion of the paper the results with p <0.05 (they only have a nominal ...
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R - Bonferroni correction with p.adjust(), what's the correct n value?

I am trying to get the Bonferroni correction right. Let's suppose I have a dataset with 100 p-values, 20 significant at minimum the 10% level (p-value < 0.1) and 80 not significant (p-value >= 0.1)...
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P values all equal to 1 after using bonferroni or hommel

Several topics are talking about this but in my case my p values are generated differently. My p values will be calculated simulating $N$ (in this case 5000) random gene groups of size $g$ of the ...
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591 views

Wilcoxon test with multiple testing: which correction for p values?

Please, I'm not very confident in statistics, and I'm trying to respond to a reviewer for a paper on the following issues: In my experiment I observed 15 babies during a test where they were free to ...
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1answer
256 views

Bonferroni correction: how does it work?

I already read the answers here: About the Bonferroni correction, but I still don't understand the concept completely. Assume the following hypothetical case, where I perform an ANOVA test to ...
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How to Control Familywise Error Rate in a series of Planned McNemar Comparisons

I have paired binary responses from same subjects under 9 different conditions. I conducted Cochran's Q which indicated that there significantly different pairs exist. I want to follow up but NOT ...
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231 views

Bonferroni correction for pairwise proportion comparisons for more than one outcome level

Suppose I have an event that can have 3 different outcomes. This event is recorded for 21 different factor levels for a total of 100 times, and each time an outcome happens it is counted (so I am ...
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Type-I error adjustment for simple effects when 2x3 factorial ANOVA interaction only is significant

I have found several questions and answers that skirt around my problem but I haven't been able to deduce a clear solution. My situation is this: I ran an experiment with a 2x3 factorial design (call ...
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794 views

Multiple paired t-tests. Bonferroni number of comparisons?

I have done 9 paired t-tests, to see if there are significant changes in pre and post measurements of three variables (FFMQ-SF, GSE, WEMWBS), across three groups (Engagement level: minimum, medium, ...
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80 views

Unusual Bonferroni correction

Assume my hypothesis is: "Light supports the performance of students." The experimental setting consists of two room conditions that students are randomized to. The "light" group takes a test in a ...
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90 views

comparing the means of multiple distributions

I wish to compare the means of three independent data sets. These are exam scores that are from class A and class B and class C. Class A and B are normal and tested ok for homogeneity. A T-Test ...
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39 views

Multiple comparison correction, when?

I am not sure about how many test I have in the following scenario: I collect 3 measures of a persons performance in a task (m1, m2, m3). I also collect data on two anatomical features (A1, A2). Then ...
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Multiple hypothesis test

I have some questions about multiple hypothesis test. Situation 1: We have 1000 p-values, all of them are less than 0.0 5. We may say there are 50 false positive (1000*0.05) in these p-values. ...
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Chi-square difference test: how to adjust for the number of tests?

How should I adjust for the number of tests I do when using the chi-square difference test, where the null hypothesis of the test is that two models do not differ? I am using this test in the context ...
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How and when to use multiple comparison tests

There seems to be some variability in WHEN multiple comparison tests such as Bonferroni or FDR might be implemented. Type 1: One might carry out multiple one-way ANOVA's to see whether or not there ...
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bonferroni adjustment with multiple groups

I have 3 categorical metrics on cars Quality (values are high, medium , low) , Reliability (values are high,medium, low), Avg Life (long, medium, short) and I have 4 groups A,B, C,D and they give ...
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Bug in SPSS bonferroni correction?

I just read some topics that discuss how SPSS corrects the p value shown and it keeps 0.05 as significant when applying bonferroni correction. The problem that I have is that I'm running a repeated ...