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.

learn more… | top users | synonyms

1
vote
0answers
11 views

a priori power analysis for ANOVA plus post hoc test

I would like to perform an a priori power analysis to calculate required sample size for data to be analyzed using one way ANOVA and Tukey HSD post hoc test. (I want to determine pair-wise which ...
0
votes
0answers
24 views

Different sample sizes, skewed data and unequal variances

I am a bit confused regarding best statistical test to use for my data. Here is the details: I did a study to compare two independent groups; 31 patients and 60 healthy controls. I have around 50 ...
1
vote
0answers
33 views

Multiple Hypothesis Testing with Categorical Variables and Alternatives

Suppose we have a variable $Y_i$ which is a binary categorical variable, and we have a variables: $X_{i,1}$, $X_{i,2}$, ....$X_{i,n}$ ($i=1,2,....N$ where $N$ is sample size, and $n$ is the number of ...
5
votes
3answers
203 views

Does Bonferroni apply to inference from parametric and non-parametric models?

I have run 6 independent-samples t-tests, and 4 Mann Whitney U tests. When applying Bonferroni correction, does it apply across all 10 tests? My hypotheses are that there will be 4 significant ...
0
votes
0answers
8 views

The use of MANOVA, ANOVA or t-tests for Likert-style data

I have two groups I would like to compare on a series of Likert-style mood dimensions (e.g. Very Sad - Slightly Sad - Neutral - Slightly Happy - Very Happy). The sample sizes are 19 and 63. The data ...
1
vote
1answer
41 views

How to say “the statistical significance of our result is stronger”?

I'm doing a Bonferroni correction, after which our result is still significant at the 10% level. Since my multiple outcomes are highly correlated, for which the Bonferroni is too conservative, I want ...
0
votes
0answers
33 views

Bonferroni correction in MANOVA

so if I've done a MANOVA and followed that up with Bonferroni correction and found that only 2 out of 7 variables are significant (whereas before there were a few more) does that mean that only these ...
1
vote
1answer
21 views

When is it ok to NOT control for multiple comparison?

My initial feeling was never. But I notice that whenever people write up a larger study (or a meta-study) they do not adjust the significance thresholds of the individual measurements to account for ...
20
votes
3answers
2k views

Why aren't multiple hypothesis corrections applied to all experiments since the dawn of time?

We know that we must apply Benjamini Hochberg-like corrections for multiple hypothesis testing to experiments based on a single data set, in order to control the false discovery rate, otherwise all ...
2
votes
2answers
75 views

Incremental adjustments of $\alpha$ for multiple hypothesis testing?

Given a nominal significance level of $\alpha$ for a single hypothesis test, I understand that if you do multiple tests, $i = 1$ to $m$, then according to Bonferroni's correction, the significance ...
0
votes
0answers
41 views

pairwise.t.test in R returning no value

I am a noob in R, and have been breaking my head for the past three hours over the pairwise.t.test in R. My data frame is structured as given below. My data frame has the age of flight of bees and the ...
0
votes
1answer
29 views

Assumptions on Multiple Comparison - Bonferroni and others

I was asked for an alternative procedure to multiple comparisons which does not require independence of the multiple tests being applied. I´ve found some readings where Bonferroni´s correction is said ...
2
votes
1answer
48 views

Bonferroni Correction - When not to use it

In a discussion with another researcher, I was informed that it is not always necessary to perform a Bonferroni correction on exploratory research if a lot of testing is required (for example, if many ...
3
votes
2answers
43 views

Is Bonferroni correction used for multiple levels, multiple factors, or both?

Bonferroni correction can help us correct our alpha values in multiple statistical testing. One aspect that I am confused on: Is Bonferroni correction used when we have multiple levels (Does this ...
2
votes
1answer
56 views

Why is Bonferroni considered a conservative multiple comparison tool?

Bonferroni correction seems to be known as a "conservative" way to determine. Why is it called conservative? Is it because it assumes independence among all tests? Sort like Naive Bayes?
0
votes
0answers
12 views

Testing many proportions against each other…use logistic regression?

If I have an A/B/C/D/E/F/G test - i.e. I'm testing 5 test variations vs a control - what corrections do I need to make to be able to determine the best variation? To find winners vs the variation I ...
3
votes
0answers
57 views

Difference between one-way ANOVA and all pairwise comparisons with Bonferroni correction [duplicate]

If you have five groups and you wish to know if there is a significant difference between any of the group means, you would have to do 10 pairwise comparisons to test all possible pairs of means. You ...
1
vote
0answers
20 views

Appropriate Correction for 2 proportion test? --with example--

Below is an example of frequency data between observed and expected proportions. Can I simply run a 2-Proportion z test here? Or, would I be violating assumptions? If I were to run dozens of z tests ...
4
votes
1answer
62 views

Do I need a Bonferroni correction?

My study has me running several regression analyses to investigate my hypothesis, and I am struggling with the multiple comparisons problem. I have three separate metabolites as predictor variables, ...
3
votes
1answer
44 views

Least conservative multiple testing correction

This is a general question regarding multiple testing when making confidence intervals. Suppose I have an unknown vector $$\mu = (\mu_1, \dots, \mu_p).$$ My goal is to estimate this vector, and ...
0
votes
1answer
51 views

How come we have Bonferroni correction when we have ANOVA analysis?

ANOVA analysis can be used to determine the significance of multiple groups. Why do we need Bonferroni correction to re-compute the alpha values? ANOVA solves the problem of multiple testing by ...
0
votes
0answers
24 views

Fisher's exact test + Benjamini-Hochberg correction for 100s of tests gives 100s of significant terms; Question about representative subset?

We are doing Fisher's exact test for 1,000 items (genes) in a population of 20,000 (genes). After that we use Benjamini-Hochberg multiple-test correction. We get over 200 significant results (Gene ...
1
vote
1answer
27 views

Multiple Comparison correction for temporally correlated tests

My data consists of N~200 cells. For each cell I am seeing the response to a stimulus for the next 300ms, in bins of 5ms (150bins total). In order to get confidence bounds for each bin on whether a ...
0
votes
0answers
15 views

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 ...
0
votes
0answers
24 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 ...
0
votes
1answer
43 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 ...
0
votes
0answers
45 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 ...
3
votes
1answer
50 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 ...
0
votes
0answers
39 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 ...
0
votes
0answers
8 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 ...
1
vote
0answers
18 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 ...
0
votes
0answers
72 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 $B_0$ ...
0
votes
0answers
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 ...
0
votes
1answer
42 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 ...
2
votes
1answer
48 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 ...
1
vote
0answers
33 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: ...
0
votes
0answers
313 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: ...
4
votes
0answers
89 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 ...
0
votes
0answers
47 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 ...
0
votes
1answer
102 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 ...
1
vote
1answer
62 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 ...
0
votes
2answers
103 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). ...
1
vote
1answer
62 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) ...
0
votes
0answers
221 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 ...
0
votes
0answers
39 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 ...
1
vote
1answer
126 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. ...
0
votes
0answers
30 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 ...
2
votes
1answer
42 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 ...
2
votes
0answers
141 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 ...
1
vote
0answers
163 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 ...