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Questions tagged [p-value]

In frequentist hypothesis testing, the $p$-value is the probability of a result as extreme (or more) than the observed result, under the assumption that the null hypothesis is true.

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Related low p-values that do not meet statistically significant thresholds

If I were to have multiple related measures, each with "low" p-values that do not quite meet the threshold of significance, could the fact that multiple measures produce a general trend with ...
Jaxton Winder's user avatar
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Significance of the coefficients of a multinomial mixed regression built with npmlt function

I fitted (using npmlt function) a mixte multinomial regression model which ran without errors. I expected that the outputs of the model include p-values that I didn't find. My need now is that someone ...
Romaine TCHEDJI's user avatar
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Hypothesis testing on sum and product of beta random variables

In population genomics, a locus at which all the individuals of a population have alleles equal to the reference allele is called a fixed locus. I am working on a model to obtain the expected number ...
Josh9999's user avatar
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My questions are related to the outputs of model built with npmlt function [closed]

I fitted (using npmlt function) a mixte multinomial regression model which ran without errors. I expecting that the outputs of the model includes p-values that I didn't find. My need now is that ...
Romaine TCHEDJI's user avatar
0 votes
2 answers
41 views

Test whether my new method's type I error rate correctly matches chosen alpha

I am testing two different methods for hypothesis testing, bootstrapped likelihood ratio tests, and likelihood ratio tests assuming an asymptotic distribution. I would like to see if the number of ...
A Friendly Fish's user avatar
4 votes
2 answers
143 views

Are there alternative statistics to a p-value in NHST?

Sometimes, when the logic of p-value is explained and motivated, it happens in the following way: The concept of a random sample is introduced, together with the need to consider the possibility that ...
Sam's user avatar
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Determining the p-value of a test statistic, which is not distributed according to a commonly known distribution under the null hypothesis

Currently I am working in R on a project that aims to identify Dragon King events (massive outliers) in large datasets. These outliers appear for example in the city sizes in England, where London is ...
user25936873's user avatar
3 votes
1 answer
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Testing for difference in trends of binary-parameter proportion/fraction versus continuous parameter between two (or more) different populations

I have three samples of objects: sample X (total = 138), sample Y (same basic class as X, but located in a different environment; total = 186), and sample Z (total = 996). For each object, I have a ...
Peter Erwin's user avatar
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The problem of double adjustment of p-values in multilevel models with categorical predictors

I have a set of around 30 multilevel models which have the same predictor variables (and the same cluster variable), but different outcome variables. Since there are so many models, I want to perform ...
J. Doe's user avatar
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0 answers
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correlations and adjusting p-values

I want to determine the correlation and p-value between one variable and all of the others in an R data frame, so I created a correlation matrix with cor_mat, and ...
Steven Morrison's user avatar
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Why can we use RMSE as a proxy for the effect size of a VAR or Granger Causality?

My question here follows a previous question by me here: Is there a meaningful option to compute something like an effect size for Granger Causality?. In this previous question I asked for options to ...
Philipp's user avatar
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Is there a meaningful option to compute something like an effect size for Granger Causality?

I am running Granger Causality (GC) analysis using statsmodels.tsa.stattools.grangercausalitytests between several time-series pairs. The time-series pairs used for ...
Philipp's user avatar
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1 vote
1 answer
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Comparison of two test metrics

I'm trying to compare two test metrics (Metric A and Metric B) to determine which one better predicts a delta value, which represents a Euclidean difference. I am unsure how to determining which ...
agf1997's user avatar
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9 votes
4 answers
492 views

Variable is significant in multiple linear regression but not in t-test of the subgroups

I am getting different p-values for a variable in t-test and its coefficient in multiple linear regression so I am unsure which one to believe. As an example, my hypothetical dataset consists of ...
user416771's user avatar
5 votes
4 answers
392 views

Ideal test/p-value calculation for difference in means with small sample size and right skewed data? [closed]

I need to compare a response variable between two different groups. My control group has 205 observations while my comparison group only has 2 observations (unfortunately this is the nature of the ...
Alexander's user avatar
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How to measure Statistical Significance for calculated Sensitivity, Specificity, Precision, Accuracy and f1 values?

I am trying to understand how to calculate one or more measures of statistical significance to display alongside metrics I've calculated from my data. Abbreviations I am using in the rest of this post:...
Natalia's user avatar
6 votes
1 answer
218 views

Estimating effects in the presence of a mediator

Suppose that one is interested to compare the effect of biological age versus "cognitive age" on a variety of outcomes. Cognitive age is measured by testing intelligence. The outcomes are a ...
Sam's user avatar
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Why Do Different MANOVA Test Statistics Produce the Same Approximate F and P Values in R?

I am using the manova() function in R to perform multivariate analysis of variance on my dataset. I have tried using different test statistics such as Pillai's ...
Praful Kumar's user avatar
10 votes
2 answers
114 views

What is the proper formatting of very low p values? [closed]

Generally, I believe in giving exact p values rather than something like " p < 0.05". But, sometimes, the p value is extremely low, on the order, say, of $10^{-10}$ or even lower. Under ...
Peter Flom's user avatar
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Sufficient number of data to determine whether a model fits the data well

I was wondering if, chosen a proper mathematical model, there is a minimum number of data that allows us to state if the model fits well the data or it doesn't. I'll explain better my question. Let's ...
Mattia's user avatar
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12 votes
3 answers
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Why do physicists use sigma while biologists use p values/posterior probabilities?

I work in the analysis of biological data, and am familiar with the use of maths to determine a test statistic, and the comparison of this test statistic with a threshold to evaluate a hypothesis. ...
User65535's user avatar
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1 answer
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Help interpret these P-values [duplicate]

What does it mean when the model P-value comes out larger than alpha but the P-value for one of the main effects comes out smaller than alpha? The actual ANOVA is below. Alpha is 0,0027.
Ladislav Révay's user avatar
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1 answer
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Are the p-values obtained on the same sample using synthetic AA tests (Monte Carlo) independent values?

Let's say we have the following procedure. We take a fixed sample of size n and perform the procedure 1000 time: we divide (split) it equally into 2 groups; we calculate p value using the F function (...
Романов Андрей's user avatar
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Different P-Value and AIC before/after standardization [Python - Statsmodels]

I am investigating the correlation between environmental variables (15 continuous variables grouped as 'DHIs' in the code below) and fox occurrence (binary), using logistic regression / Python ...
Andrew Norfield's user avatar
5 votes
2 answers
54 views

Am I using the fisher.test() function incorrectly? Can't replicate p-value found in research paper

I've been trying to replicate the results of this research paper (The Tale of Cochran’s Rule: My Contingency Table has so Many Expected Values Smaller than 5, What Am I to Do? by Kroonenberg and ...
conejitadelaluna's user avatar
1 vote
1 answer
41 views

How do I do the p-adjustement in statistical tests?

context: a study about which type of bread and/or filling attracts ants the most I have a table with 3 columns : the number of ants attracted, type of bread, type of filling. The question is : do ...
Moez Daly's user avatar
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0 answers
13 views

Which statistical test to use for comparison of influence of two independent variables?

I am conducting a research of "Comparison of Influence of Parents' and Teacher's Attitude Towards Math to Anxiety of Students in Math" Now my null hypothesis: There is no difference in ...
Vince Legaspi's user avatar
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0 answers
35 views

How can I combine p-values estimated for individual variables within a single dataset using different statistical methods?

I'm analyzing a multivariate dataset with two classes (case/control). I've calculated p-values for each variable to test their discrimination perfomance using two different methods: 1) univariate t-...
Guillermo Q's user avatar
20 votes
5 answers
2k views

Having a second bite of the data-apple without p-hacking

My hypothesis concerns intervention versus control in a randomised controlled trial (between-subjects, n=500 per group, online survey experiment). I pre-registered that my primary test would be a ...
Amorphia's user avatar
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1 vote
0 answers
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Can the One-Sided Mann-Whitney U Test Have a Composite Null Hypothesis?

Let's say there's an i.i.d. sample $X_1, X_2, \ldots, X_{n_1}$ from a distribution with the CDF $F$ and $Y_1, Y_2, \ldots, Y_n$ from a distribution whose CDF is $G$. As far as I know, the null ...
Milos's user avatar
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3 votes
4 answers
86 views

Interpretation of high p value of a coefficient in linear regression [duplicate]

In a medical article, the multiple linear regression model included some coefficients with low p values but also some with p>0.05. How can I interpret these high p values and should they be be ...
0 votes
1 answer
67 views

Coefficient in Regression Analysis

I am running regression on two variables (independent and dependent). If the results show p-value > 0.05, it is not statistically significant. Does this mean we reject the coefficient as well? If ...
Bestmiler's user avatar
2 votes
0 answers
76 views

untrustworthy p values? emtrends following lmms with fixed effects of different levels of repetition

Edited to clarify further 23/04/24: I have a fairly complex linear mixed effect model in R and I believe that there are issues to do with repeated data when running my post hoc tests. The model ...
Hannah Gibbs's user avatar
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0 answers
31 views

Difference between a comparison of independent variables t.test and linear regression model of one category?

The thing is I am trying to obtain confidence intervals of several variables (food, blood chemical analysis...) of patients who are divided in two groups according the intervention. Until now I was ...
Javier Hernando's user avatar
1 vote
0 answers
21 views

Benjamini Hochberg Procedure [closed]

I am working on a problem for class related to multiple testing where I would like to run the BH procedure with a known $\pi_{0}$, denoting the proportion of hypothesis that are truly null, given ...
Harry Lofi's user avatar
9 votes
6 answers
264 views

Why was the term "significance" ($\alpha$) chosen for the probability of Type I error?

I'm currently studying "Statistics 1" as part of my Computer Science degree, and I'm having trouble understanding the concept of "significance." We were provided with the following ...
Yup8's user avatar
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0 votes
0 answers
17 views

How to test for statistical significance on a multi-country dataset?

I am attempting to test for statistical significance between treatment and control groups, with data from 7 countries, using a Welch 2-sample t-test [t.test() in R]. 6 out of 7 countries have ...
Corey Chin's user avatar
6 votes
2 answers
852 views

Regressors Became Statistically Insignificant Upon Correcting for Autocorrelation

I am using Stata and used the regress command and received $p$ values that indicate the regressor is statistically significant. However, after plotting the residuals, I noticed there was clearly an ...
William H's user avatar
0 votes
0 answers
68 views

Understanding of nominal p-values in sample size calculation

I need your help to understand the R-Output. In this example, two interim analyses were planned. The adjusted p-values are shown below. However, I am still not clear what the nominal p-values mean. ...
Anonyme Ironikerin's user avatar
2 votes
1 answer
82 views

Why p-values as $P(p≤\alpha | H=1)≤\alpha$ and not $P(H=1 | p≤\alpha)$?

That's my question, as if I start from the definition of a $p$-value ($P(p≤\alpha | H=1)≤\alpha$ ) and apply Bayes rule I arrive to: $$ P(p≤\alpha | H=1)=P(H=1 | p≤\alpha)\frac{P(p≤\alpha)}{P(H=1)} ≤\...
R.V.N.'s user avatar
  • 123
3 votes
2 answers
113 views

Statistical Thresholds for RNA-Seq Analysis: Considering the Intersection of Treatment Effects

I'm conducting an RNA-seq experiment involving worms exposed to chemicals A, B, and A+B to observe mRNA changes due to exposure. I'm particularly interested in identifying mRNA changes in the A+B ...
Netanel Cohen's user avatar
5 votes
1 answer
91 views

Fisher's exact test - how to find tables "as extreme"

I attempted to understand the computation of the Fisher's exact test through programming using this formulation: The Fisher exact test computes the p-values by finding the probabilities of all ...
user210804's user avatar
1 vote
0 answers
39 views

What is a good p-value adjustment for a permutational analysis like pairwise PERMANOVA?

I am comparing plant community responses to experimental treatments using the pairwise.permanova function in R. However, there are no clear answers regarding which ...
Reesamu's user avatar
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1 vote
0 answers
18 views

Imputing a Continuous P-value Distribution from Discrete P-values [closed]

I'm exploring methods to create a continuous-like P-value distribution from discrete P-values. For example, consider the process where a balanced coin is tossed four times per experiment to note the ...
irahorecka's user avatar
1 vote
1 answer
47 views

Comparing sequence of unfair coin flips with different predicted probabilities

Suppose we have $n$ independent coins, each of which has an unknown and different probability of coming up heads. We have a magical machine that guesses the probabilities of each coin coming up heads. ...
differentiableapple's user avatar
0 votes
0 answers
29 views

Comparing averages of two groups

Say I want to check if the averages of 2 groups (A and B) are the same. For each member in group A, there are some observations; same applies for group B. If I want to take the average of A and B, I ...
Andrei's user avatar
  • 1
2 votes
2 answers
228 views

Can anyone work out the P value from this graph?

Can anyone work out the p value just based on the graph below? I cannot understand how this is calculated and what additional information I would needs to work it out.
Sorina Bolache's user avatar
0 votes
1 answer
62 views

Relationship between p-value and Cramer's V

Is there a relationship between p-value and Cramer's V value after conducting Chi-square test for independence... is for Cramer's V value of about 0.13 the associated p-value is of about 0.001 or it ...
Rusul Raed's user avatar
1 vote
0 answers
26 views

Can p-values from permutation tests be interpreted as a measure of effect size between group?

I'm conducting a research project involving gene expression analysis. We've developed a method to calculate a score from a given set of genes, A. To evaluate the ...
zhang's user avatar
  • 113
1 vote
0 answers
65 views

How to proceed when the observed effect is smaller than the Minimum Detectable Effect?

Given an A/B test with an already defined sample size and variance, a power analysis was conducted to estimate the Minimum Detectable Effect (MDE) of a proportion. After the experiment was concluded, ...
loglossbb's user avatar

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