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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P-values in univariable quantile regression [on hold]

I'm using SAS for quantile regression and I was wondering what the code is for outputting p-values in addition to CI values. Multivariable quantile regression automatically does it but univariable ...
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Multiple test correction procedures for multiple regression with dependent predictors

A researcher is employing OLS multiple regression to examine the independent effects (i.e., partial correlations) of a moderate (~8) number of theoretically-relevant predictors on some outcome. The ...
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28 views

What happens when there's a one-tailed hypothesis test and the results are in the other tail?

For example, let's say I'm using a one-tailed t-test to see if a box of Lucky Charms cereal has more than 100 marshmallows. I know the consequences of using a one-tailed t-test and how it wouldn't be ...
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How do one interpret the results of wilcoxon-mann-whitney test in SAS?

I have done the Wilcoxon test in SAS. My class variable is race. I got a low p-value. What exactly does that mean?
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1answer
23 views

Data analysis: how to compare 2 variables from each subject across 3 groups of 200 subjects?

New here and not a statistician, am MD doing research. Need advice on best method for data analysis. I have 3 groups of 200 subjects each. We collected 2 data points (A,B) from each subject. Baseline ...
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27 views

(Dis)Advantages of correlation vs. $R^2$ vs. p-value of linear regression for two variables?

I would like to know what are advantages and disadvantages of $R^2$ vs. correlation (e.g. cor() in R) vs. p-value of linear regression for two variables/features? ...
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1answer
11 views

Trying to migrate from P values to CI… how to know when to reject null hypothesis? [duplicate]

So, I know that if we get a p<= 0.05 (95% CI), I know that the null hypothesis can be rejected. Now my question is how do I do that with CI? Eg. in the table below A17S group has a CI of ...
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1answer
45 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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29 views

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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30 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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14 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
23 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
15 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? ...
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1answer
126 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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13 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
43 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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9answers
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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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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 ...
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1answer
14 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 ...
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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 $CDF_A$ ...
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2answers
77 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
29 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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980 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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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
20 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
29 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
28 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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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
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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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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
15 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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18 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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44 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
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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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21 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 ...
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40 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
51 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
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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
35 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
33 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 ...
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70 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 ...