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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Why does a p-value of 2.4 indicate a very small probability that rejecting H0 is incorrect?

I am working with body temperatures in R, conducting a t-test. It is widely believed that the average body temperature for healthy adults is 98.6 degrees Fahrenheit. The body temperatures of $n = ...
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378 views

Hypothesis testing. Why center the sampling distribution on H0?

A p-value is the probability to obtain a statistic that is at least as extreme as the one observed in the sample data when assuming that the null-hypothesis ($H_0$) is true. Graphically this ...
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32 views

Can you derive Standard Deviations from a raw mean difference and p-value?

I have mean averages and a p-value, which I assume was of a t -test. This is the information provided to me: Treatment N =121 Control N=107 treatment mean = 356.700 treatment control= 357.560 ...
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30 views

Spearman's rho correlation coefficient and p-values

I am analysing data from questionnaires. I have 344 valid responses. When I run the spearman's rho correlation test to see if there's any correlation between students' home province and their ...
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68 views

How to correctly calculate the type I error in a two-step clinical trial when stopping after the first step?

I just finished reading the following article by Berger & Berry (1988) in which they explain how subjectivity enters statistical analyses. One of their examples concerns a clinical trial with ...
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Correspondence Analysis and p values

CA was originally designed as an exploratory method, and did not supply p values. So when mapping data one might have a table that looked at 3 texts of 500 words, each with counts for 10 words in ...
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385 views

A p-value greater than 0.05 means that my results are meaningless?

I just came across a correlation factor of 0.70 but p-value 0.054, does this mean that my correlation factor is completely meaningless and I should try to provide more samples?
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19 views

P for trend for quartiles in linear regression in SAS

I am using PROC GLM in SAS to run a linear regression model and have a continuous exposure variable that for a secondary analysis I have categorized into quartiles. I know I can use a contrast ...
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10 views

Random Walk: Right p-value method?

Based on a stochastic matrix/graph $G$, I want to conduct a series of random walks to get an idea which are frequent interaction partners for a starting node (not only connected by the first edge). I ...
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56 views

What statistical test to use when some participants receive multiple treatments?

I have N participants, some of them are on drugs A, B or C, exclusively (no overlapping). I know how to do the hypothesis test in this case. But what if I have a small subset, say n, of these ...
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150 views

Simple linear regression, p-values and the AIC

I realise this topic has come up a number of times before e.g. here, but I'm still unsure how best to interpret my regression output. I have a very simple dataset, consisting of a column of x values ...
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78 views

The true meaning/difference of alpha values and p-values

EDIT: I may have been confused by the confusion of others. In any case, it helped a lot when I came to know that the $p$-value is stochastic. It does make sense, given the $p$-value is a ...
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34 views

How to find the p-value of a t-test using the critical value?

I keep looking over the lecture and they just seem to skip how they get from the critical value to the p-value, but we need to be able to do this for the exam! So I've calculated the test statistic $(...
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R : qvalue package - smoother or bootstrap method for pi0 estimation

I've a bunch of 500 p-values and I want to estimate the pi0 (proportion of true H0). When using the qvalue R package, two method can be used (smoother or bootstrap). Both giving very different results ...
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20 views

How to generate t-test with data sets on different scales?

Let's say you repeat an experiment on two different days. On day 1 you get the following data: Day 1 ...
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33 views

Can p-value for Spearman correlation be calculated from only the correlation coefficient and the sample size?

When searching for p-value, I realized that the p-value for Pearson correlation can be calculated by simply knowing the correlation coeffiecient and the sample size, as illustrated in this website P-...
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36 views

Chi-square and R: Calculate matrix of statistical significances between results

First of all, I would like to apologize if this is an duplicate of an earlier question. I find it hard to believe that I am the first person to ever have this sort of problem, but I am so far out of ...
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9 views

How to Perform Fishers Exact Test with Uncertain Data?

Fishers exact test uses a hypergeometric distribution to compute the p-value when given two classification aspect and there respective group frequencies in a given dataset [ref: https://en.wikipedia....
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41 views

Significance testing for Markov chain transition probabilities

I'm modeling a sequence of discrete states as a first order, stationary Markov chain. I'd like to calculate a matrix of p values (one for each possible transition). Say the state at time $t$ is $S_t$. ...
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41 views

Which test to calculate the p-value?

so I have a data set of 1500 proteins. I then identify a set of 50 proteins and lets say 40 of these 50 have a certain function. I then draw 1000 random samples of size 50 from my initial 1500 protein ...
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Adjusting p-values (mixed effects logistic regression)?

Quick question regarding adjustung p-values.... I preformed a logistic mixed effects regression model and used Wald likelihood ratio test to select model parameters. I received comments back from a ...
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30 views

p-values in sign test

If we are given a list of $n$ independent measurments $\{0,0,1,0,1, \dots, 0,1,1,0,1\}$ of binomially distributed random variable $X$, we can use the sign test to check, whether the difference between ...
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hypothesis test observed to simulated, z-score or not?

Lets say we have data set with an x and a y variable. We have an effect size from a linear model called of ...
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27 views

Hypothesis testing for difference in proportions when pooled population proportion is known

The example I use below to frame my questions is a bit contrived, but I am hoping the answer will help to clarify my understanding of more complex, related issues. Suppose we know in advance that the ...
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21 views

What to do if a categorical variable has some components that are not statistically significant?

I'm trying to construct a univariate prediction model using logistic regression in order to predict credit default likelihood from overdue level in telecommunication companies: https://drive.google....
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38 views

Regression ceoff. p-value as a 'summary measure' of 'indication of relative importance'

I have a paper in front of me (peer reviewed, etc.), which states "comparison of the P values for [the covariates] gives a good indication of the relative importance of each [covariate] for ...
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large sample and significance

I have a very large sample (790 million rows), and in this case, even small difference are determined to be significant, p <0.0001. The 95% C.I.s are very sharp. In this case, these tests (t-test, ...
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Why do p-values have uniform distribution for normally distributed data [duplicate]

I generated some random data using rnorm() in R made a matrix X of 10,000 rows and 1,000 rows. The I generated 1000 zeros and ones using runif(). I stored the rows corresponding to 0 in Y in one ...
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25 views

Dunnett T3 test interpretation

i have result from a Dunnett T3 test using package DTK in R. The result do not give me any p-value but only "Diff", "lower CI" and "upper CI". i can understand the difference between groups as the ...
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Why does Bayesian p-value involve the parameters in addition to the data?

On page 146 of Gelman's Bayesian Data Analysis, Gelman discusses Bayesian p-value as a way to check the fit of the model. The idea is to compare the observed data ($y$) with data that could have been ...
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24 views

calculate p-value for AFT survival model

I am using Spark ml library to do some survival analysis. Here is the documentation. After training an AFT survival model, I cannot get the p-value directly as in R. What is available for the model ...
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How to test an interaction effect with a non-parametric test (e.g. a permutation test)?

I have two categorical / nominal variables. Each of them can take only two distinct values (so, I have 4 combinations in total). Each combination of values comes with a set of numerical values. So, I ...
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Prevalence of the “vote counting” method in literature reviews

In my youth I can remember reading some papers (in psychology most likely) which as part of their literature review included a table of past results with no details provided other than whether the p-...
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p-value interpretation of Jonckheere Terpstra:one-sided or two-sided

I am using the Jonckheere-Terpstra test in order to validate the pooled t-test results. Basically, I like the JT test because of its non-parametric nature. Basically, I am now trying to understand ...
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32 views

Intuitions from standard deviation to p-value?

A cake is specified by a 3-vector $x=(x_1,x_2,x_3)$, where $x_i$ is the percentage of the $i$-th ingredient, and therefore $\sum_ix_i=1$. I have a price list $y$ for different $x$'s: ...
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Hypothesis testing with no sample or standard deviation, is this is a trick question?

The question I was asked is as follows: A website received 6802 page views last week. Does this provide evidence at a 1% significance level against the claim that the website receives on average 1000 ...
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227 views

Do p-values assume an unlikely event has already happened?

According to this thread What is the meaning of p values and t values in statistical tests? a p-value essentially lets me compare the probability of tail-end (unlikely) events occurring and judging ...
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17 views

Mixed-effect models for repeated measures - problems with the “Significance level”

I am trying to fit a linear mixed-effect model to my dataset to see the relationship between a self-reported questionnaire and some physiological data. I've created a first model including all the ...
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15 views

Why does a low p-value mean there is sufficient evidence to reject the null hypothesis? [duplicate]

As I understand it, a p-value is the prob of getting something as far or farther out in the tails of a normal distribution than the observed t value. source In other words, $$\Bbb P(\text{value ...
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29 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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11 views

Can I extrapolate a mean difference from the t-statistic?

I have the t-statistic, df, p and cohen's d for the one-tailed independent samples t-tests on the difference between a parameter for cases and controls. I would like to obtain a mean difference and ...
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Can I obtain a mean difference from fold change data, number of participants and p values?

I have gene expression in fold change for cases vs controls. Therefore, below I have 4 times the gene expression of gene x in the cases compared with the controls. I have the number of participants ...
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32 views

Interpreting pvalue in the light of known power

I'm puzzled with the interpretation of a pvalue in the light of known power Let's say I study the association between a dichotomic variable (a treatment) and a quantitative one, which is my primary ...
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25 views

Calculating p-value based on Chi-Square vs Z-Test incl Standard Error

I have been testing the significance levels for my various a/b tests. Degree of freedom is 1 so there's not a lot of complications here. So far I've been calculating my results using Chi-Squared ...
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1answer
37 views

Does the p value for logistic regression depends on odds ratio or logit?

The p value in a logistic regression is given for the B estimates. But what if I'm reporting odds ratio instead of logit. Do the same p values apply?
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116 views

Robustness of correlation test to non-normality

I'm trying to reconcile two seemingly opposite statements about robustness to non-normality of the Pearson's correlation test statistic (where the null means "no correlation"). This CV answer says: ...
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Best approach for calculating confidence score (p-value) - for Bayes models

This is a generic question on the best approach for giving a p-value to a "most likely" solution given by a graphical Bayes model. I am building a graphical model in Stan, for finding the most likely ...
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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 ...
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Contradictory results of the ADF test in R [closed]

I used the urca pacakge in R to run the ADF test and got the following: It seems to me the results are quite contradictory: Using the statistic, we fail to reject the null hypothesis; However, ...