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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Adjust p-values for multiple comparisons

I want to evaluate if a proposed modification M* to a base classifier M is better in terms of accuracy. Both, the base classifiers M and their respective modifications M* are tested on N datasets. To ...
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28 views

Why is the reported p-value in papers is so less than 0.05 in wilicoxon test? [duplicate]

0 down vote favorite I have been testing my two vectors using wilicoxon signed rank test and kolmogorov smirnov test to evaluate their significance of difference. I am using matlab fr this purpose ...
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12 views

Obtaining significance for mixed GLMMs on count and binary data

I'm new to the software R and am trying to compute statistics on data from experiments on the offspring of lizards from two different thermal treatments - looking specifically at differences in their ...
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1answer
21 views

Coefficients of Categorical P-Values in Regression - Condense or Apply 0?

This analysis is part of a much larger research project, but I've extracted a simple example that will fit the question I have. Y = B0 + B1 * [Day of Week] + E Day of Week is coded as 1 (Sunday)-7 ...
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4 views

Compute p-value from foldchanges taking into account level of expression

I've expression values for 1 gene for ~50 samples and I've a sample within my 50 samples, that harbours a specific alteration into this gene (i.e. the mutSample). The other 49 samples do not harbor ...
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1answer
14 views

Propensity score stratification: standard errors and p-values

While there are many tutorials on how to perform propensity score stratification, I was unable to find any example that showed the calculation of standard errors and p-values for the final estimate. ...
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39 views

What does the P value in restricted cubic spline plot mean? [duplicate]

What does the P value in the following example mean? ...
6
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1answer
85 views

Fisher's exact test gives non-uniform p-values

I am trying to apply Fisher's exact test in a simulated genetics problem, but the p-values appear to be skewed to the right. Being a biologist, I guess I'm just missing something obvious to every ...
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12 views

Meaning of $\psi$ in regard to $p$-value distributions

In Combining dependent P-values by Kost & McDermott, the notation $\psi$ is used in a way that I am not familiar with. Relevant passge: 2.1. Known Variance. Let ...
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2answers
41 views

How can you have p < 0.0001 with a sample size of 89 and a control group of 52?

From Efficacy of monoterpene perillyl alcohol upon survival rate of patients with recurrent glioblastoma (linked from Does Frankincense cure cancer?): Patients and methods It was included 89 ...
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13 views

Summary of quantile regression without st. error, t value and p value [closed]

I need the p value of the third coefficient in quantile regression but R shows only lower b and upper b ...
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10answers
11k views

Is this really how p-values work? Can a million research papers per year be based on pure randomness?

I'm very new to statistics, and I'm just learning to understand the basics, including p-values. But there is a huge question mark in my mind right now, and I kind of hope my understanding is wrong. ...
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1answer
18 views

How can I extract all the p values from a model for an individual factor variable?

Let's say I have factor variable Var_1 with 3 levels, "1", "2", and "3". "1" is the base level of the factor variable. So when I run a linear regression, I get a p value for each level of that ...
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0answers
20 views

Calculate p-values based on many distributions without knowing which the test statistic is from

I have many (20) normal distributions of the probability of a certain event occurring. Each of these 20 has n>1000.I have an observed proportion from a separate sample that I want to compare to ...
0
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1answer
10 views

Correlogram q-statistics of residuals

I am currently try to get information from the correlogram of residuals in eviews from a certain equation; I am supposed to understand if residuals are white noise or not and to adfirm that they are ...
2
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0answers
30 views

Two sample one-sided Kuiper Test and KS-statistic

With the KS-Test it is possible to conduct a two sample one-sided test between two different random samples $A$ and $B$ to test whether one CDF is larger or smaller than the other, i.e. is $CDF_A$ ...
2
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2answers
72 views

Why does the p-value double when using two-tailed test compared to one-tailed one? [duplicate]

Since this has been marked as a duplicate, I want to clarify that it's not about critical values of one- vs two-tailed tests, but the calculation of the p-Value in this case. I get that in a ...
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1answer
27 views

Kuiper's Test P Value in R

I am trying to implement a kuiper's test on a set of data and looking for an R package (or other program) that can give a p-value without monte carlo simulation or only a range of p-values. All of the ...
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3answers
964 views

What does a p-value of exactly 1.0000 mean?

I have a table of pairwise comparisons using paired t-tests, which I produced using the following code in R: ...
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2answers
34 views

Testing the variance component in a mixed effects model

Say $y=X\beta+ Zu +\epsilon$ is our mixed effects model where $u=(u_1,..,u_r)$ and $u_{j} \stackrel{i.i.d.}{\sim} N(0, \sigma^2_{a})$ for $j=1,...,r$ and $\epsilon=(\epsilon_1,...,\epsilon_n)$ are ...
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48 views

Why does my p-value = 0?

I created a vector that is 329 rows long, with each row containing a z-score. I derived my degrees of freedom by counting up the number of rows (329) and subtracting 1. Then, I computed a test ...
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1answer
30 views

How to deal with linear regression intercepts with high p-values in dichotomic classifier?

I have used a simple multivariable logistic regression (as you would get by default glm() with logit in R) in a problem of dichotomic classifier with approx. 100 predictors, i.e. quite a lot of ...
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1answer
17 views

Given a correlation matrix and sample size, how to calculate which correlation coefficients are statistically significant?

Suppose you are given a correlation matrix and a sample size. How do you calculate which correlation coefficients are statistically significant? If there are $K$ variables then there are $K^{2}$ ...
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1answer
27 views

How to identify the ideal dose, when the doses were given to different numbers of patients?

I have six groups of patients. The groups contain different numbers of patients (i.e., 30 in group1, 70 in group2, etc). Each group gets a different dose of a new drug (i.e., group 1 - 20 mg, group ...
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29 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
21 views

ADF: Reject or keep null hypothesis (difference p-value & test statistic)

I'm working at my thesis and wanted to test my time series for Stationarity by using the Augmented Dickey Fuller Test with the program R. When I received the output, the p-value was close to zero, so ...
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1answer
24 views

logistic regression backwards selection

I am somewhat new to R and trying to polish my logistic regression. I am testing if my risk factors(cruise, age, sex, and year) have a significant effect on my dependent variable, MPS infection (named ...
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22 views

Different mean squares reported for aov and lmer

I have a mixed effects model with 2 Locations 4 Blocks (nested in each location) In each Block I dug a hole and took soil samples at 10 Depths My variable of interest is nitrate concentration ...
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1answer
29 views

P-value of Augmented Dickey-Fuller test and KPSS test

I would like to test if the time series of the US 3-month treasury bills (monthly data from 1934 to 2015) is stationary. I'm using the ADF test in R (from the package ...
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13 views

Results from logit model using BIOGEME unexpected

I am using BIOGEME to estimate the discrete choice model (choice is made among four alternative routes). I am having hard time with modeling using BIOGEME, and expecting help on this. I have dataset ...
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1answer
14 views

ANOVA test mean against predefined constant

How can I calculate the p-value (statistical significance) if my hypothesis asks for specific mean values? I suppose this can be somehow calculated using ANOVA, but I could only find examples where ...
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17 views

GLMM test P-value and inference

I am analyzing results of my artificial predation experiment using GLMM (glmer in R) where response variable is count and predictor variable [a-categorical factor with 2 level;b-categorical factor ...
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42 views

Spearman's rank correlation has p-value zero?

It looks like R's cor.test returns p-values of exactly zero if the real p-value is very low. For example: ...
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2answers
99 views

Why reject, not accept $H_0$ when $p$ value less than $\alpha$? [duplicate]

Let's say ABC drug company claims their medicine cures 90% of patients. Now a doctor conducts a trial by taking a random sample of 15 patients. Result shows 11 of them are cured but 4 are not. In ...
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20 views

How do I calculate a t-score from a p-value (gain scores and N also available)

I have this problem that only the gain scores with the p-value of a t-test are given in a scientific article. The authors neglected to report the t-test statistic and I'm stuck on figuring out how to ...
2
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1answer
39 views

Can I get an Odds Ratio (or other effect size) from two proportions and a p-value?

I am conducting a meta analysis that is comparing dichotomous outcomes for two groups. So for each study, I have the proportion of the outcome for both groups and the sample size of each group, and I ...
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1answer
27 views

Scientific P Value with adjusted R Square [duplicate]

I am running Spearman correlation between 2 variables weight and freight both being numeric. The output I have received from correlation is P value - 0.00E+000 and Rank R Squared is 0.61 and which ...
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51 views

Embarrassingly easy stats question

I have a large set of values (1000) that are each a measure of accuracy for a large set of corresponding models that were generated using random data. I want to compare a single measure of accuracy, ...
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2answers
45 views

P-value vs Type 1 Error [duplicate]

I am trying to understand the relationship of a p-value vs Type 1 error rate. My understanding of one interpretation of a p-value is the following: "the p-value tells us the probability of making a ...
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1answer
13 views

calculating significance of common genes from different comparisons

we are having difficulties calculating the significance of our between-group comparisons. We did multiple differential expression Analyses of different time-points and mutations. We analysed the ...
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1answer
34 views

How to correctly combine p-values?

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
31 views

Correlation Analysis of Standarized Testing Data

I need some insight on how to correctly analyze some data using correlations. The nature of the data and research endeavor is as follows: I have two independent samples of different sizes that ...
0
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3answers
67 views

Type of p value to select from those given by software

I'm a medical student and pretty new to statistics, struggling with some things. I am currently undertaking a research project on dilated kidneys in foetuses and the outcome in childhood. I have some ...
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11 views

Analysis of PValues Matrix

in clinical environment I'm setting up a model to identify fraudolent behaviours from specific sites, calculating for each site some aspects that could lead to a p-value (this approach is based on a ...
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0answers
3 views

how to accept or reject hypothesis based on asymp.sig [duplicate]

i just wanted to know how to accept or reject null hypothesis based on chi square value obtained in spss null hypothesis is no influence on celebrity endorsement on consumer buying behaviour ...
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16 views

Dickey-Fuller Test

I am very new to R, and am really struggling to interpret the results. This is for the CHF-USD exchange rate returns for 1999-2015. What is the "cut off" % the ADF test uses, so when can i reject the ...
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Scipy.stats.anderson_ksamp negative return values for test statistic

Ok, so I've been trying to run this test on the the iris dataset to see if it flags the clusters within the data as samples that aren't from the same population. from sklearn import datasets iris = ...
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1answer
92 views

Finding p-value based on Poisson Distribution

I'm having trouble understanding my homework that involves p-values. Here is the context of the problem before I discuss the processes I've gone through: Suppose a company which produces fire alarms ...
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Generating t statistics from p values - binomial test multiple comparisons

I am using the binomial test to generate a series of p values. However, my method of multiple comparisons correction that I wish to apply to this series requires that I also have the corresponding t ...
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25 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 ...