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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14 views

Interpreting the results of Chi-Square test

I have the following data: ...
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1answer
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parameter n in p.adjust function in R [on hold]

I'm quite confused about the n parameter in p.adjust function. p.adjust(p, method, n = length(p)) where n could be changed. but the default is length of p as stated in the documentation. So in my ...
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Should I correct p values when the exact same dataset is not being used for multiple comparison?

What I have to do? Two courses (A and B) students CGPA and percentage of class attendance is given. I have to compare CGPA of two groups (group is based on attendance - high vs low) regarding ...
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The calculation method of post-hoc power in t-test without welch's correction

【About this thread】: This thread is divided from the following threads: What is the post-hoc power in my experiment? How to calculate this? I cut out for when Welch's correction is not ...
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Same value P-Values - Holm-Bonferroni

When using a Holm-Bonferroni adjustment method or the like, how to you treat multiple p-values of the same value when ranking? For instance, I have the unadjusted p-values: ...
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Should I trust the $p$-value in statistical tests?

I got into a debate with my supervisor over a recent paper. The test of correlation in a sample of 77 participants yielded a p-value smaller than 0.05. After removing a few participants (because later ...
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Significance Calculation for Difference in Percent of two samples

I have a test and control group. Each has a current year(CY) and prior year(PY) order rate, as well as sample size. From my understanding, I can calculate the significance of the Year over Year(YOY) ...
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Obtaining p-values in a robustlmm mixed model via Satterthwaite-approximated DFs of the equivalent lme4 model?

I've used lme4 to fit a mixed model and could obtain p-values by using the lmerTest or afex packages. However due to heteroskedasticity (Levene Test) I also fit a robust model (rlmer command in the ...
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Multiple testing Partial correlation matrix

Suppose we have a data set $\textbf{X}=\{X_{1},X_{2},...X_{p}\}$, $X\in R^{n}$ and a partial correlation matrix $\Omega=[\omega]p\times p$. Inferring the partial correlation network is equivalent to ...
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1answer
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compare p-value from two different glm (with the same response variable)

I am currently analyzing the occupancy of bat boxes and the factors that are influencing the occupancy. To determine the most significant variables influencing the occupancy I am running a glm with ...
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1answer
87 views

Applying a non-normality and non-homoscedasticity penalty to the p-value of a t-test

【My motivations】:(Add on 05/10/2019 05:23 (JST).) In the traditional textbook, method like following codes are written. (Since our purpose is not to explain what is written in the textbook, the one ...
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bootstrap testing - p value with subtraction and replication (Python)

from std.disclaimer import "Dammit Jim, I'm a programmer, not a statistician." Edited to try to make the terminology more correct and the question more clear. Mea ...
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Expressing one-sided p values of directional hypothesis tests as Bayes factors

Assume we want to test the directional hypothesis that $µ<0$. From a frequentist angle we use a one-tailed $t$-test and imagine we obtain a 1-sided $p$ value of say 0.07, which then would imply ...
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109 views

Why do we not always use the closed testing principle for multiple comparisons?

From the Wikipedia entry: Suppose there are k hypotheses $H_1,..., H_k$ to be tested and the overall type I error rate is $\alpha$. The closed testing principle allows the rejection of any one ...
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Which means “p-value” in clusters analysis? [closed]

For example, a software has generated 5 clusters with the following p-values: Cluster1: 0.058 Cluster2: 0.252 Cluster3: 0.882 Cluster4: 0.972 Cluster5: 0.997 Objectively speaking, what these p-...
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1answer
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Logistic regression interpretation in SPSS statistics

I observed a very strange behavior while doing logistic regression, univariance analysis and correlation analysis. I have dependent binary variable and several independent variables that should be ...
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Different results for simulated and closed form distribution of T-statistic under the alternative hypothesis

While running some simulations to get a better grasp of the concept of statistical power I stumbled upon an unexpected result. I was trying to simulate the sampling distribution of test statistic $T$ ...
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Does running multiple similar models lead to p-hacking?

In my analysis I am testing a lot of similar models. I have two variables (let´s call them A and B) and a whole bunch of other variables (C1....C10). All models have the same approach: It is always ...
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Calculated sample size and calculated p-value in two independent t test [closed]

I would like to know the relationship between sample size and p-value. When comparing two independent means. Sample size calculation 1) Expected difference between two means: 2.8 2) Expected ...
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1answer
97 views

Interpretation of p-values in ARIMA model

I am starting my journey in time series analysis and forecasting and I'm currently facing some doubts. If I fit an ARIMA model to my data and I get for example an ARIMA(2,1,2) in which the p-value ...
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How should I calculate the p-value for a bootstrapped Pearson correlation?

Should I look up the $p$-value using a $z$ score from the mean of bootstrapped correlation coefficient estimates ($r$) and the standard error of those estimates ($SE$)? $$ z = 0.5 \ln\left(\frac{1+r}{...
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R: Attribute Overepresentation in a cluster

I performed hierarchical clustering in a dataset with 4 categorical variables (2 nominal, 2 ordinal) in R using hclust and daisy ...
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Why is rejection of null hypothesis not a case of prosecutor's fallacy?

Here is what my understanding is: p-value - probability of finding the observed, or more extreme, results when the null hypothesis (H0) of a study question is true which is to say p-value$=P(...
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Is a confidence interval the inverse of a p-value? [duplicate]

I've recently encountered the claim that a confidence interval is 1-$\alpha$, (where I assume $\alpha$ is a p-value). e.g. that a p-value of 0.05 is equivalent to a 95% confidence interval. I ...
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p-value for two small Bernoulli trials

I am no statistician, but I am among the more statistically inclined at my workplace, so my coworkers consult me from time to time. I don't alway give the right answer, but I'd like to think I give ...
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Very small p-value after performing ANOVA TEST (small sample size)

I performed an ANOVA test on some data from samples and obtained a very small p-value in the order of e-200. My samples size are not big (12) wand I'm using 30 samples. Samples are not related at all ...
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Different formulas for two-sided mid $p$-value ($2\times2$ table setting)

I'm interested in testing independence of two binary variables in a $2\times 2$ table: i.e. $H_0: \theta=1$ against the two-sided alternative $H_1:\theta\neq 1$, where $\theta$ is the odds-ratio. ...
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29 views

Does higher F-statistics have higher p-value?

This post is a continuation of my previous post. After reading all comments and answer, I think that F-statistics tells us whether explanatory variables in a model is significant or not, as the null ...
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1answer
31 views

How to adjust P-Value for Multiple Tests

I'm not sure if this is answered or not because there's a lot of these questions and the ones I looked at didn't answer this. If I were to say, have five independent variables of interest and one ...
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1answer
32 views

Calculating P-Value of a Z-Score without using Z-Table [duplicate]

I couldn't find any videos or documentation that shows how to calculate p-value of a z-score without using z-table. Isn't it possible or is it that hard? I know i can use scipy to get that ...
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1answer
63 views

Choose the best predictive model based on p-value on coefficient, $R^2$ and $F$-statistics

Given the following models with their respective p-value for their coefficient, $R^2$ and $F$-statistics, I was asked to determine which model will give the best prediction based on the information ...
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How to get P value of correlation coefficient here

I am using this package to get correlation coefficient : https://godoc.org/gonum.org/v1/gonum/stat#Correlation It works well but it does not give P value of the correlation. Other functions in this ...
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61 views

How to use chi-square for ranking?

I came across this recent KDD paper titled as Concepts-Bridges: Uncovering Conceptual Bridges Based On Biomedical Concept Evolution. In page 6 of the paper they have used ...
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p-value and hypothesis testing [closed]

(The p value) Which one of the statements about the p value is correct? a) The p value is the predefined probability of making a mistake when the null hypothesis is false. b) The p value is the ...
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Compute effect size from simulated NULL distribution

I computed a empirical p-value (permutation test) where I compare my real value to simulated values (N=100,000). In the end I've a distribution like this (vertical line = my real value). For the p-...
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1answer
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Can I get a p-value testing statistical significance between two coin flipping rounds?

i'm a graduate student (biology program) with minimal experience with statistics. I have two questions relating to my project that i'd love help with! The first question is how I can take a single ...
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Should I remove empiral p-values = 1 before multi-testing?

I performed a permutation test in order to compute empirical p-values. To simplify I compare a vector with real data R to N=100,000 simuated vectors ...
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1answer
26 views

Which statistical analysis test is more appropriate to calculate p-value?

I am trying to determine if the increases seen in gene expression from a certain time-point to another are significant or due to biological variation. I know that I should calculate the p-value but I ...
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1answer
28 views

Multi test correction and hypothesis testing

I have 9 datasets with one predictor and one target attribute. For each of the dataset, I am testing for a single hypothesis - whether the attributes are associated. I have got the following based on ...
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i got a very high p-value

i conducted a test to see weather smoking have a relationship with pregnancy period or not and the mean and sd were almost the same between smokers and non smokers moms however i got a high p-value i ...
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If p-value is exactly 1 (1.0000000), what should the confidence interval limits be to support null hypothesis being true? [closed]

This is purely a hypothetical question. A very common statement is that $H_0$ is never true, it's just a matter of sample size. Let´s assume that for real there is absolutely no measurable ...
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2answers
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Understanding P-Value with respect to the Level of Significance [duplicate]

The definition of P-value is the probability of obtaining a sample that is more extreme than the ones observed in your data, assuming that the null hypothesis is true. That 's very well-explained in ...
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1answer
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P-values in multiple comparison t-test

I'm a biologist trying to teach my college class about the issue of multiple comparisons with t-tests. I've explained that the alpha value must be "combined" so to speak from each of the related ...
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1answer
23 views

When to correct for multiple comparisons (with specific reference to emmeans in R)?

I notice that emmeans::emmeans() will only correct for multiple comparisons within groups and not between groups. This means that if you perform a series of ...
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1answer
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Hypothesis test for the difference of two means, should I consider annualized or monthly returns?

I have 10 years monthly returns. I calculated annualized return multiplying the mean return over the period for 12. Then I calculated the excess returns as difference between the annualized mean ...
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1answer
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Am I taking crazy pills here or this A/B testing tool's documentation dead wrong?

In the documentation here for a popular A/B testing they say, For example, if you run an A/B testing experiment with a significance level of 95%, this means that if you determine a winner, you ...
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In the specific context of baseline traits of study participants (see ref.), what is p value? What's being tested and is it pointless? meaningful?

(Please assume readers already have a basic understanding of what p is in general.) The is it pointless part of this question seems to be YES; that part of the question is similar to, and I'd guess ...
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1answer
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Approximating p-values from Bayesian posterior distribution

I'm preparing a manuscript for publication in which I have fit a mixed linear model using Bayesian regression. I'm assessing whether group A is bigger than group B. In the paper, I have reported the ...
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Use Bayes' rule to $p$-value

In hypothesis testing, one usually calculates $p$-value by assuming that null hypothesis holds. In wiki page of $p$-value, first sentence verifies my statement above. To write $p$-value using ...
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I tested serial correlation and got a p-value of 0.13, can I accept that there is no serial correlation?

My data are 6 variables × 68 data. Null hypothesis is there is no serial correlation. Is p=0.13 too small? it is very close to 0.1. The significance level I choose is 0.05 though.