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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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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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32 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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36 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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69 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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25 views

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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26 views

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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27 views

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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17 views

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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40 views

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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79 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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14 views

How to Control the Type-1 Error Rate for T-Tests Used to Understand Sig. Interaction Effects

Basically, I ran a repeated measures ANOVA between groups R and D with one within-subjects factor with 2 levels. A significant interaction was found. To understand what was driving the interaction I ...
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21 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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37 views

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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36 views

Defining “family” in the Family Wise Error Rate (FWER) correction

I know that the term "family" in FWER isn't defined very clearly in the literature and although one definition that is widely accepted, "All tests that are performed", a lot of applied statisticians ...
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1answer
112 views

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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56 views

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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106 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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216 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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42 views

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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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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17 views

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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1answer
134 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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50 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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44 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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Questions about Bonferroni and power statistics

Thanks in advance for taking the time to read my questions. In a project of mine, I have performed a vast series of regression analyses (one for each measuring point, if which there are many). With ...
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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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44 views

Bonferroni/Holm correction when performing chi-squared residual analysis

Let's say I am performing two t-tests and one chi-squared test for a 5*2 table (for example levels of education vs. sex). I am further interested in which categories of education differ among sexes, ...
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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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58 views

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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18 views

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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Error correction within factorial GLMMs

Below is toy-data and analysis for a bog-standard factorial longitudinal GLMM ...
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110 views

Adjustment for multiple tests for a mediation with multiple DVs? (Process/SPSS)

I hope my question has not been addressed in another post; I could not find any response to my issue. I'm conducting a mediation analysis with 1 IV (X), 1 mediator (M), and 4 DVs (Y). I use Process, ...
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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 ...
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How to use Bonferroni correction - correct by no of parameters? No of models per dependent variable?

I have a simple question about when corrections such as Bonferroni should be applied. Say I have a research question for which I have three separate dependent variables, and run three separate models ...
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564 views

85% Bonferroni family-wide (simultaneous) CI for lm in R

The code confint(model, level = 1 -0.15/length(coef(model))) was recommended by https://stat.ethz.ch/pipermail/r-help/2005-March/067570.html However, I have ...
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234 views

Bonferroni correction for Wilcoxon signed rank test with 6 related samples?

I am comparing scores of the same group of people over 7 days. I first did a Friedman's test to know where the differences were between the 7 days and I did a Wilcoxon signed rank test for the Post ...
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61 views

Should P-values of continuous variables be corrected?

Usually, when doing multiple tests to compare means of categorical variables, it is advised to do some correction of the P-values to control the probability or proportion of false positives (...
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Do I need to “correct”?

I am testing whether a certain learning intervention affects student achievement. I have two groups of students (control and experimental) with 16 students each. I have their pre-test and post-test ...
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284 views

differences between pairwise.t.test and p.adjust

I have searched to see if already answered but couldn't find an exact response, but apologies if its a duplicate. I am also very new to R and programming so apologies if the code is messy and I am ...
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92 views

p-value Inequality?

I was trying to go over this paper by Dudoit, Shaffer and Boldric when I came across this statement on page 78 (under section 2.4: Control of family-wise error rate): $P(P_j\leq x \vert H_j)\leq x,$ ...
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148 views

Bonferroni correction vs. asterisks signifying significance levels

There is convention concerning the use of asterisks to represent levels of significance. I am sure there are others, but let's stick to this one for now: Convention for symbols indicating statistical ...
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2answers
310 views

Bonferroni correction: elementary question: when do I reject?

Question practically rewritten as from some answers&comments became clear that I am not understanding the semantics and context. The "procedure" for Bonferroni is clear to me, my problem is a ...
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1answer
289 views

Multiple comparison correction (Bonferroni vs. Holm Boonferroni)

I have four questions: If i have to run a test on 4 colors; red, blue, green, yellow. I ran the same test 4 times (one time on each color). (H1~H4) If i already have a predefined or existing reason ...
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104 views

How to apply Bonferroni correction across multiple regression experiments?

I have 5 variables: A, B, C, and D. A and B are two different scales and are my dependent variables. C (categorical) and D (continuous) are fixed effects. C is also a categorical variable having 3 ...
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1answer
748 views

Correction of p-values for multiple regression models with multiple comparisons

I was asked to do a correction of p-values for my analyses, but I'm not sure what p-values I am to correct, and presuming I'm using Bonferroni, what is the number that I am dividing the .05 level with....
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20 views

Bonferroni Correction When Using Dates as Data Points [duplicate]

I have a test and control group in which I tested the impact of a sale on baseline revenue across a 3 week period (test received sale, control did not). ...
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35 views

Using a different p-value threshold depending on number datapoints

I am working with protein data at different time-points. After log transformation many proteins show a linear incorporation over time. Therefore I can use a simple linear model to study its trend. ...
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426 views

Bonferroni bound and FDR: compute p-values

Suppose I have measured the activity of $N=20$ genes for 102 subjects (50 with cancer and 52 normal). Based on the available data, I compute the following table: ...
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327 views

Do I have to apply Bonferroni correction for U-test

I believe my question might be quiet easy for you to answer. I tried to do some research on that topic myself but failed to come to a conclusion. If I understood correctly, Bonferroni correction is ...