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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Bonferroni correction after hypergeometric test

I have a small doubt regarding a Bonferroni after running an hypergeometric test on genomic data. Let say I have a population of 379876 output data(integer numebers), and this population is clustered ...
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19 views

When shall I use multiple comparison adjustment if I perform a series of Chi-square?

I am presenting some descriptive statistics about % of access to a service in different regions (12) of a country in my bar graph over two time period points. As the results are based on 12 2X2 tables ...
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25 views

Some new questions re the Bonferroni correction

When the Bonferroni correction is used, what is the actual test that is conducted? For example, is it the t-test? If you know the formula, that would be great. SPSS gives P values for each pairwise ...
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19 views

Does testing multiple interaction terms result in multiple testing problems?

I have been testing interaction terms in a regression model using likelihood ratio tests, and dropping any terms from the model if insignificant. I do not want to assume a priori that there are no ...
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1answer
34 views

What is the correct terminology for one/two-tailed p-values and how do I apply the Holm-Bonferroni correction?

I have been struggling to reconcile my (very basic) understanding of P-values with the approach of one of my colleagues and it appears to come down to interpretation of p-value terminology. This is ...
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30 views

Interpreting Results from Multiple Comparisons and Joint Significance test

I am conducting a study to test whether the manufacturing quality of a machine has an effect on its failure time. I am using a hazard model with a dummy variable to identify machines manufactured with ...
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7 views

When performing a factorial design two-way ANOVA, why do we conduct a mean seperation test on the data after finding no interaction?

I am a college student who must perform a factorial two-way ANOVA on a specific experiment. My professor told me that I would have to test for interaction among the data points first. If I find no ...
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12 views

Multiple Comparisons Corrections within Subgroups

I've got a set of data points with "scores" that belong to a series of subgroups (not necessarily disjoint). That is, I may have a point that belongs to groups A, B, and D, and then another point that ...
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50 views

Interpretation of Bonferroni confidence interval

When simultaneous confidence intervals for $B_0$ and $B_1$ are built by the Bonferroni method, with a confidence coefficient of $\gamma=0.90$, we can interpret that in 10% of the times $B_0$ ...
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41 views

How to approach statistical corrections (e.g. Bonferroni) on a series of multiple linear regressions using the same set of predictors?

I have a somewhat medium sample (n=380). I am running a series of 16 multiple linear regressions, each of them being some kind of performance index related to a scale or a questionnaire (I might drop ...
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13 views

how to (not) plot all pvals if many contrasts are done

I have run an ANOVA and then a Bonferroni test, using 8 groups. Therefore, the significant pvalues are many and showing them in a plot is messy. How would you recommend to approach this ...
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1answer
37 views

Mann-Whitney significance and multiple hypothesis testing significance

I am performing various comparisons using the Mann-Whitney U test. Because I'm comparing various groups simultaneously, I would am also correcting the p-values for multiple hypothesis testing using ...
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1answer
45 views

Why do I need a Bonferroni correction if we are evaluating our primary outcome?

We have completed a study comparing control with vitamin D supplement and with bone building drug. The primary outcome is change in bone mineral density. My statistician states that because we are ...
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32 views

Hypothesis testing with finite interval as null hypothesis

There exist two-tailed tests ($H_0: \mu = c$) and one-tailed tests ($H_0: \mu \leq c$ and $H_0: \mu \geq c$). I am interested in the case of the null hypothesis being an interval, that is $H^{ab}_0: ...
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164 views

Finding the Significant Differences (with p-values) in a 4x2 Chi-Square Table Using SPSS

In short, I would like to learn how to discover where the significant differences lie within a 4x2 Chi-Square table and report the significant findings with a p-value, preferably using SPSS. Setup: ...
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77 views

Cherry picking and low p-values

Let's say I run a lot of univariate OLS regression models, say 200,000, with 50 data points, then cherry pick the best one (highest r-square). If my $p$-value for this model is way less than ...
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31 views

Post-Hoc Chi-Sq test - conclusions drawn from comparing individual categories

My question is very similar to this one: (Post hoc $\chi^2$ test with R), but I'm still confused, and tried to provide as much detail as possible. I have two categories of students: Domestic and ...
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1answer
59 views

Fisher's exact test and Bonferroni correction

I compared Survivability (live or die) using tibial Intraosseous (io), humerus io, tibial io, intravenous epinephrine for patients who have cardiac arrest. We had a control group that received no ...
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1answer
47 views

criteria for choosing a post-hoc tests

After eg. ANOVA there are several post-hoc tests out there (e.g. Tukey, Bonferroni, etc.) but what are the criteria for choosing one over the other? If one is more conservative, shouldn't we use it ...
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2answers
80 views

Multiple testing adjustment in linear models

I have troubles with multiple testing correction (For example, bonferroni adjustment. I'm aware that it's not most correct one). ...
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1answer
50 views

Dependence, independence, multiple testing, and alpha error correction

although I have studied psychology and feel I should know a lot more about issues such as this one, I have a quite basic question (or maybe not so basic question, considering all the fuss about this) ...
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168 views

Bonferroni post hoc test in R for repeated measure ANOVA with mixed within and between subjects design

I need to perform a Bonferroni post hoc test in R on a table with three within subjects factors (Emotion, having 5 levels, Material, having 4 levels, Shoes, having 2 levels) and one between subject ...
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29 views

Bonferroni correction for multiple testing and overlapping groups

I have allele frequency observations from a large geographic region that can be logically subdivided into smaller areas in a number of different and meaningful ways. If I were to test these ...
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1answer
104 views

Repeated Measures ANOVA and the Bonferroni post hoc test different results of significantly

I am doing an Repeated Measures ANOVA and the Bonferroni post hoc test for my data using R project. The ANOVA gives a significantly difference between the data but not the Bonferroni post hoc test. ...
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26 views

What to do after a significant Exact test?

I have significant Fisher exact tests for a 2x3 and 6x3 contingency table. All I can get from it is that the observation regarding columns and rows are not random. But I don't know which combination ...
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1answer
37 views

Does the bonferonni correction change the outcome of the p-value or is it just changin what you accept as significant?

For some reason I can't seem to integrate the bonferonni corrected p adjustment into my multiple comparisons t test in r so I need to do each of my 3 tests individually. What I wondered was do I need ...
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82 views

Bonferroni Adjustment and Assumptions?

I'd just like to get clarification on something. When you perform a bonferroni adjustment (dividing the alpha level by the amount of tests you want to do, if say you're doing multiple ANOVAs) do you ...
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87 views

Bonferroni correction of bootstrap generated p values

I have run a multiple regression analysis with 900 independent variables and bootstrapped this analysis 1000 times, with replacement, to generate bootstrap p values. When I looked at the results, I ...
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1answer
34 views

Do I need to use a Bonferroni adjustment?

I am using three different ANOVAs to determine significance across two treatment levels. Because we only have two species I chose to run the same set of analyses for each of the species instead of ...
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1answer
175 views

Bonferroni Correction p value in SPSS [duplicate]

I have run an analysis on data using SPSS. I have a repeated measures design with 7 conditions. I chose to do pairwise comparisons to see where the effects lie and used the Bonferroni correction. If ...
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54 views

Bonferroni Corrections for multiple control groups

We recently ran a marketing test at work where we are looking at the amount of customers that make a transaction at the store if we do not email them, Email them, email them AND send them a physical ...
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1answer
145 views

Is there a consensus on adjusting alpha for multiple contrasts if the main effect is significant?

After talking to a couple of statisticians, reading some book sections, internet articles, and forums like this, I am still unclear about multiplicity adjustments of post hoc tests and contrasts. ...
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65 views

Standard multiple regression and multiple dependent variables. and bonferroni correction?

I have a question regarding running multiple regression equations with multiple dependent variables. Three independent variables and 3 dependent variables. A colleague advised me to conduct three ...
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378 views

Confidence intervals from the Holm-Bonferroni test?

I'm a newcomer in the problem of multiple comparisons. I wonder how to calculate confidence intervals for Holm-Bonferroni method? I know that for Bonferroni method we can just change the confidence ...
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52 views

Bonferroni adjustment according to which families?

We have 17 subjects in a crossover design of three groups: Challenge agent (CA) CA+ compound of interest (CI) CI - Our data proves this has no physiological effect, and is thus not used in ...
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1answer
87 views

Bonferroni method for multiple comparisons with 1-way layout

My statistics book describes the Bonferroni method of doing multiple comparisons with a one-way layout as essentially performing a t-test with each pair of interest with a significance level scaled ...
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41 views

Post-hoc test on 3 groups comparison

I have 3 groups each with 6 values. After performing acceptable levene test for Homogeneity of Variance, I performed Anova on my data. It was significant, and I started to perform post-hoc test. The ...
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111 views

Significant Friedman's test vs. non-significant multiple comparisons

I am currently running a randomized, placebo-controlled, cross-over design for a new type of intervention. This intervention is compared to a placebo and another more conventional type of treatment. ...
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56 views

Multiple t-tests and Bonferroni

I have two independent groups (healthy weight and overweight) and want to compare three different variables between the two groups (BP, cholesterol, body fat). I know I need to run three separate ...
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164 views

Fisher's exact test for 3x5 contingency table in R with post-hoc? Consistently with using Fisher or Chi-squared?

I'm struggling with some (relatively simple) stats questions for some work I'm doing in R, and can't seem to find answers online... I have a factorial response variable of habitat type of a species ...
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29 views

Which means difference test to use?

Currently, my data is count data and I am analyzing it in Proc Glimmix in SAS. My data focuses on how many times birds from two treatments performed stand, sit, forage, ect.... So it basically looks ...
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118 views

Multiple test correction for categorical variables with many levels

I am creating a binary logistic regression model with the inputs as a single categorical variable with 100 levels. My goal is to find which level of the categorical variable is most likely to result ...
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1answer
1k views

Bonferroni correction on multiple Kruskal-Wallis tests

My data consists of 3 groups, and 6 variables. The data are not normal so I want to use non-parametric tests to uncover significance. The first thing I wanted to get your opinion on is, is it ...
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338 views

Report in ANCOVA: descriptive means or estimated marginal means?

I have conducted an analysis of covariance, ANCOVA, followed by Bonferroni post-hoc tests, on SPSS. I want to report the differences between my groups in text (APA style) and in a corresponding bar ...
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112 views

How is plot of p-values distribution related to calculation of the false discovery rate?

I'm running t-tests for all combinations of pairwise comparisons of average length of stay for patients among 30 hospitals. My first approach was to use a Bonferroni corrected significance level of ...
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314 views

p-value correction for multiple t-tests?

My dataset consists of $n$ genes, each of them described by a vector of expression values, $5$ for "healthy" individuals, and $5$ for "unhealthy" individuals. I am going to run $n$ t-tests (one for ...
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1answer
110 views

multiple pair wise nonparametric comparisons

is it possible to perform multiple pair wise nonparametric comparisons (generally using a Mann–Whitney test) and adjust the significance level used for the decision criteria using a Bonferroni-type ...
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306 views

Post-hoc with Bonferroni a correction after ANOVA with repeated measure in SPSS

does somebody know where I can find the t value of post-hoc tests with Bonferroni correction when using SPSS.From what I get so far, I only see p values. Should I add a command in the script? Thank ...
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437 views

How to best approach ANOVA with multiple response variables that might be correlated and Bonferroni Correction

I need some help verifying a simple analysis. I have completed a simple two factor experiment of more or less equal sample sizes. Let's assume for the case of this question that the sample sizes are ...
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12 views

Appropriate correction for tests for determining best of family

I have a sample of $N$ instances of a problem (assumed to be independent samples of an infinite population of instances). To each of these instances I apply $M$ methods, and record how quickly they ...