Questions tagged [combining-p-values]

Methods for combining p-values from several hypothesis tests with the same null hypothesis into one aggregate p-value, such as e.g. Fisher's method and Stouffer's method.

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How to interpret the harmonic mean p-value?

I am working on a multiple comparisons problem for several hypothesis tests and have come across the harmonic mean $p$-value (HMP) for combining the $p$-value of these tests. Specifically, I am using ...
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Combining tests: Maximum test statistic method but one test is a permutation test

I want to combine two tests $A,B$ for the same null and alternative hypotheses. The motivation is that it has been shown that test $A$ has higher power in some situations whereas test $B$ has higher ...
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1answer
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Combining p-values from permutation tests from single subjects

I have a question that's very similar to this question: Combine multiple independent permutation tests My 'issue' is exactly the same: I have 20 subjects and I used permutation tests to determine the ...
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33 views

How to calculate p-value?

I'm looking at two sets of data: timestamps for some known events, and timestamps for events measured by an instrument. I want to determine whether that instrument is "seeing" those events. ...
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1answer
43 views

combined p values from different hypothesis

I am currently working on a project in which I'm simultaneously identifying and quantifying protein in k samples. Experimentally, for each of the k samples, I have n identified proteins, with a p ...
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1answer
17 views

After derivng a test statistc using p-value combination method, what is the associat null hypothesis

First I generate two one-sided p-values from independent samples using null hypothesis $H_0: \Delta\leq0$, so that $p_1$ and $p_2$ are generated. Next, I apply the inverse normal combination function $...
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41 views

Combining coefficients of two independent linear regression

I have two datasets. Dataset 1 has $P$ measurements of dependent variable $Y$ and independent variable $X_1,,,X_N$. Dataset 2 has $Q$ measurements of dependent variable $Z$ and $X_1,,,X_N$. $Y$ and $Z$...
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1answer
47 views

Fisher's method for combining p-values

I'm using the sumlog function in the metap package of R, and have a few questions about the nuts-and-bolts of this function: 1)Some of my p-values are reported as '<0.001'. How do I include these?...
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1answer
64 views

Meta-analysis with only p-values

I am doing a systematic review on the risk factors that predict infection after liver and pancreatic surgery. These risk factors include parameters like age, sex, smoking, pre-operative chemo etc. I ...
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24 views

Cobine p-values, same data, same test, different labels

I have a dataset (300 samples vs 4000 features), I'm trying to extract meaningful features related to two condition A and B. ...
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3answers
79 views

Combining p-values when the trials are independent but their number is data-dependent and random

Consider the following scenario (it's just a motivating example, not something I am doing for real): I run a trial, drawing an i.i.d. sample $S_1$ from population $P$, to test a hypothesis $\mathcal{H}...
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1answer
69 views

Test for multiple samples of ordinal data

I have 10 independent samples of ordinal data ranked 1-3. I also have predicted ranks for the same data set. I want to test if the predicted ranking matches the observed ranking at a rate better ...
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1answer
37 views

Marginalizing statistical test results in a two-factor grid

Consider the following toy problem. Suppose that we have several food groups: meat, vegetables, fruit, etc. For any given pair of food types A and B, we ask whether people that eat both A AND B have a ...
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1answer
66 views

Interim analysis: probability of stopping

Say we do some time-varying study. We check yearly if early stopping is necessary, which is done via interim analysis (O'Brien-Fleming stopping boundaries). The 4 p-values for stopping in 4 ...
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1answer
44 views

How to test the significant of multiply chi square tests

I know that if I have a model from which I have a very large sample, so that I can create a null distribution. And I also have an experimental sample, I can use the ChiSquare test (or FisherExact test)...
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1answer
42 views

Combining the conclusions from multiple Diebold-Mariano tests

Suppose I have two forecasting models, A and B. Moreover, suppose I have multiple datasets and I use each of these sets to perform Diebold-Mariano tests. My aim is to find out which of the two models ...
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333 views

How to combine multiple p-values into one? [closed]

I have the data of 841 genes along with the p-values which represents the association of that gene in a particular tissue (Aorta in this case) with some diseased phenotype. I want to combine the p-...
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Does a uniform distribution of many p-values give statistical evidence that H0 is true?

A single statistical test can give evidence that the null hypothesis (H0) is false and therefore the alternative hypothesis (H1) is true. But it cannot be used to show that H0 is true because failure ...
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1answer
437 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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1answer
1k views

Problems with Fisher's Method for combining p-values

I am using Fisher's Method to combine p-values, and have noticed some strange behavior for large p-values and large $n.$ In my case I have a large number of not statistically significant results(e.g. ...
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1answer
111 views

Rolling sum of 2 sample KS test results

In order to compare two lists of samples from 'before-treatment' and 'after-treatment', I am doing a two sample KS test using the ks_2samp function from Python's scipy.stats package which gives me the ...
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929 views

GLMM with highly unbalanced data and statistical power

Although I have used R to explain my question, I think and hope this is of general interest and is not off-topic here. I want to test whether the continuous variable “varA” is different between the ...
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1answer
882 views

How to achieve a two-sided combined p-value using Fisher's method?

Let's say I want to answer the question if smokers vs nonsmokers have different levels of Gene A. This seems like an obvious two-sided test. However, if I have multiple studies and I want to combine ...
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1answer
86 views

Comparing 2 p values of different sample size

I did 2 linear regression analyses. White woman (WW) N1= 50 Black woman (BW) N2= 49 Correlation btw WW's V1 & V2 P = 0.001 Correlation btw BW's V1 & V2 P = 0.013 How do i know if the 2 p ...
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1answer
275 views

Probability density Function for p-value product

I am running an experiment where I get 22,152,480 p-values in a given order, ranging from 0 to 1, but strongly tilted toward 1 (i.e. not uniformly distributed). I want to say that a given series of ...
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1answer
167 views

Combining p values: what can we say about population of studies

I have N p values (N is around 200) one for each of N independent experiments in my study. These p values range from 0.03 to 0.7 (mean is 0.3), where only 5% of p values are less than 0.05. If I look ...
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Can a meta-analysis of studies which are all “not statistically signficant” lead to a “significant” conclusion?

A meta-analysis includes a bunch of studies, all of which reported a P value greater than 0.05. Is it possible for the overall meta-analysis to report a P value less than 0.05? Under what ...
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1answer
246 views

Performing a meta-analysis of wilcoxon rank sum analyses

Suppose an experiment is done and the following is presented in a paper: median for experimental, median for control, and a WRS p-value, and (n) for EXP and CTRL arms. Now suppose experiment 2 is ...
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1answer
235 views

Suppose I have a Cramér-von Mises $p = 0.99$ and Chi-squared $p = 0.88$ of a distribution being Student's-$t$. What can I say?

Suppose I have a Cramér-von Mises $p = 0.99$ and Chi-squared $p = 0.88$ of a distribution being Student's-$t$. What can I say? What can I say about the underlying distribution's being a Student's-$t$...
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1answer
65 views

How would you compare subgroup Stouffer Zs?

p-curve analyses (http://www.p-curve.com/) use significant p-values to estimate evidential value and effect sizes. To estimate evidential value, p-values are computed for p-values (pp-values), and ...
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48 views

Can one use Stouffer's method to integrate t-values? [duplicate]

I would like to integrate T-statistics values from multiple, independent tests. How can this be done? Since my degrees of freedom are many ($n>1000$) I was thinking to use the Stouffer's method,...
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1answer
134 views

Using p-values reported as inequalities such as $p<0.05$ in meta-analysis; can I convert them to $0.05$?

I am currently undertaking a meta-analysis of the expression profile of specific biomarkers in a specific disease. During the extraction process, I extracted the name of the biomarkers and their ...
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1answer
340 views

Testing multiple comparisons of paired proportions

I want to know if a proportion increased significantly after an event, and then find out if that holds true over multiple events. I'm using a paired t-test to measure this with continuous data (e.g. ...
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1answer
386 views

Difference between Fisher's method and the sum of chi-square test statistics

I'm learning about combining $p$-values and I have a couple of (somewhat elementary, perhaps) questions. Suppose I have $n$ independent tests, each of these to test its own null hypothesis $H_0 (i)$, $...
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2answers
795 views

How to calculate probability of success based on prior p-value

The FDA often requires a sponsor to conduct multiple clinical trials prior to approval. Given the following observations in a ph2 and ph3 trial, how would you go about predicting the probability of ...
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1answer
155 views

Combine multiple independent permutation tests

I want to find out whether a neural measure measured at 12 time-points is correlated with a behavioral measure measured on the same time-points. I have data from 20 subjects. I'm hoping to perform a ...
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1answer
441 views

Fisher's combined test vs testing uniform distribution of p-values

In testing a global null hypothesis, with independent tests, the p-values are distributed as $U(0,1)$. There are many goodness-of-fit tests to check that the distribution is uniform. For example, this ...
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230 views

Reference for tail bound of chi square distribution [closed]

Fisher's method allows to combine a set of p values $p_1,\ldots,p_n$. In order to compute the p value associated with Fisher's method one needs to compute the tail of a chi square distribution with ...
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1answer
98 views

Combining different normality transformations for Fisher's method

I have 2 data sets that are applicable to Fisher's method. One has a p-value of 0.07 and the other 0.15. Neither sets were normal or homoscedastic. The first satisfied the ANOVA assumptions only with ...
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2answers
934 views

meta-analysis of p values

I am a bit confused about doing the meta analysis with my data. Given z-scores I calculate p values in a way: p.values = 2*pnorm(-abs(z)). Then I would like to ...
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0answers
93 views

Fisher's method for P-value more conservative than OLS?

I am currently observing an interesting phenomenon in my analysis. I have a simple logistic regression model for independent Inds. The model is as follows: $$\operatorname{logit}(Y) = \beta_0+\...
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2answers
302 views

Test for significant excess of significant p-values across multiple comparisons

I have what feels like a simple question, but was unable to find answers easily. The situation Let's say I have a gene microarray dataset with tens of thousands of genes and small (<100) number ...
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3answers
10k views

R package for combining p-values using Fisher's or Stouffer's method

Is there an R package (or even a base R function) that implements Fisher's or Stouffer's method for combining p-values? Coding this should be almost trivial, but I'd rather use (and cite) a package. ...
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0answers
51 views

Test of Equal Proportions with exact p-values [duplicate]

The question "Test of Equal Proportions with zero successes" showed me that using a test of equal proportions with very low or very high numbers of successes doesn't give an accurate p-value. Below is ...
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1answer
231 views

Combining very small p-values - Fisher's method gives 0

I have 30 p-values all very small (varying between $10^{-140}$ and $10^{-110}$), and I want to combine them in some way to get a single statistic. I learned about Fisher's method, but if I apply it to ...
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1answer
240 views

What are the reasonable properties of p-value combination methods when all p-values are the same?

Suppose we are testing a null hypothesis $H_0$, by combining evidence from $n$ independent tests, using a p-value combination method $M$. The combined p-value is $M(p_1,...,p_n)$. Assume the extreme ...
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4answers
4k views

Why does Stouffer's method work?

It seems like a fairly straightforward question, but when I really think about it, Stouffer's method doesn't make sense to me. This is why: Assume a two-tailed hypothesis. You first calculate $z_i$ ...
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128 views

Methods for meta-analysis: z-transform (Stouffer's approach) vs. Fisher's method vs… infinite others? [duplicate]

Fisher's method and Stouffer's approach (z-transform) for meta-analysis roughly follow the same scheme: take the p-values from some different experiments on the same hypotheses apply to them some ...
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1answer
2k views

Why is my combined p-value, obtained using the Fisher's method, so low?

I have multiple individuals, for whom I collected two time series of some parameter. For each individual, I calculated, whether these time series are correlated. So, if I have 20 individuals, as a ...
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1answer
188 views

Is there a t-test equivalent to Stouffer's z-test?

I have $k$ pairs of samples from different distributions. For each pair of samples I want to check if the samples are taken from a normal distribution with the same mean and variance. I assume the ...