Questions tagged [hypothesis-testing]
Hypothesis testing assesses whether data are inconsistent with a given hypothesis (usually a null hypothesis of no effect).
45 questions from the last 30 days
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Is there a standard way to quantify & test the benefit to one covariate by including a second covariate?
For a linear model (or glm), is there a standard statistic (and associated test) to quantify whether inclusion of a covariate increases the strength of the association between another covariate and ...
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How to permute p-values?
Recently, my colleague encountered a problem while working with a dataset, df_a, which contains gene data. Each row represents a ...
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Stouffer's Method: Restriction on underlying hypothesis tests producing p values?
When using Stouffer's method to combine p values, they first have to be converted to z scores. Does this mean that p values that are derived for example from a permutation test are not valid inputs, ...
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Not computed tests in gofstat in R
I am working on a survival analysis project. For this project, I use this dataset:
https://archive.ics.uci.edu/dataset/519/heart+failure+clinical+records
I began by importing these libraries :
...
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Multiple Test Correction in RT-qPCR Studies with Small Gene Set
I conducted an experiment using RT-qPCR to analyze the expression of a small, manually selected set of 12 genes. These genes were chosen based on their close biological relationship and their ...
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Multi Comparasion and interaction plot [closed]
I've done a Kruskal Wallis test to check if there is an effect of 2 categorical variables (independent) on 1 continous variable. After getting a significant p-value, i've conducted a post-hoc test. ...
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53
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Suitable statistical test
I have 2 groups - people that were ever active on my website and people who were never active. Activity is a metric based on some actions - both groups of people visited the website.
Each group used a ...
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Likelihood ratio test for samples from two different populations
This is basically exactly same as the post here. The answer given over there was not accurate as the null distribution specifically states $\mu_0=\mu_1=0.$
I have attempted it but am not sure if the ...
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How to find the point where a ridge 'statistically' dissipates?
Here is an image of a surface $\mathcal{M}$ of my interest.
The surface is estimated from a family of curves $z=f_x(y)$ (each curve is a measured physical profile of some object) assigned with $x$ ...
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Statistical Testing with Minimal Samples for Reinforcement Learning Algorithms
I'm working on comparing two reinforcement learning algorithms where:
Running experiments is extremely computationally expensive
Based on preliminary results, Algorithm B consistently and
...
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Chi-squared test of independence
Consider a contingency table which contains observation counts that are poisson distributed. In particular, $O_{ij}$ is $Poi(\lambda_{ij})$. If we apply CLT assuming $\lambda$ is large, then we get ...
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Question from past exam [closed]
I have a statistics exam this Friday and I encountered this question:
David suspects that the big fire of Carmel Mountain a few years ago caused a
decrease in the birth rate of deer. He sampled 10 ...
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Estimate SD[Z=X*Y] which one is correct?
Given we have a sample of two variables X and Y with sample size n. I want to calculate the standard deviation of Z = X*Y. I don't know which of the two options bellow are correct?
Option 1:
Simply ...
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How to establish statistical significance of changes in strength & direction of confounding/mediators/risk factors/effect modifiers for paired survey?
First of all, I'm new to Biostatistics (took one Intro to BioStats class more than a year ago), so please be patient with me :-) ...
I have a paired survey taken before (F0 survey) and after the ...
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Which significance test to use for a difference of means? How to be sure?
[Updated] I have two data sets containing all official recorded games played in the USA for this one sport. One data set is for the women's teams and the other for the men's teams. I'm trying to ...
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Nonparametric extrema hypothesis test based on ranks
Does there exist a non-parametric test testing the following hypothesis:
given $N$ points in $\mathbb{R}^m$ and their ranking $Y$ in $\mathbb{N}$ answer:
$H_0:$ there is no minimum or maximum (extrema)...
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Comparing the time duration to do a job
I need to compare the time duration of a production operations done by two different workers.
Basically, the raw material is divided into two independent groups: one group of objects will be processed ...
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Compare two variances
I am reading this paper
I have difficulty understanding Section 6: A Linear Time Statistic and Test.
At the beginning, they claim that $\text{MMD}^2_l$ has higher variance than $\text{MMD}^2_u$ (we ...
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What exactly is the definition of a UMP unbiased test?
I am solving exercises from section 8.3 of Hogg and McKean's "Introduction to Mathematical Statistics." I cannot proceed because the authors have not formally defined UMPU test even though ...
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In a Frequentist setting, how are we able to condition on the null hypothesis being True/False?
Paraphrasing Casella and Berger (2002): A hypothesis test is defined by a null hypothesis $H_0: \theta \in \Theta_0 $ and an alternative hypothesis $H_1: \theta \in \Theta_0^c = \bar{H_0}$, where $\...
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Is a chi squared test appropriate for this contingency matrix? [duplicate]
I have the following contingency matrix:
$$
\begin{bmatrix}
420 & 6750 \\
150 & 460
\end{bmatrix}
$$
Here the rows stand for apples and bananas, the columns stand for "...
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Is it appropriate to do a post hoc power analysis after the null hypothesis is favoured in the Mann Whitney U test? The sample sizes are unequal
Hi is it appropriate to do a post hoc power analysis after the null hypothesis is favoured in the Mann Whitney U test? The sample sizes are unequal and I want to know if it is underpowered. With posts ...
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Testing equality of coefficients from two different regressions with Seemingly Unrelated Regressions
I am running two regressions, one nested in the other.
$$ y = \beta_1 X + \epsilon_1$$
$$ y = \beta_2 X + \beta_3 Z + \nu_2$$
I would like to assess whether the coefficient of X is the same or not ...
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A test to check whether two sets of proportions are _not different_
Is there a test to check whether two small sets of proportions are significantly not different?
For example, consider the two sets of proportions
...
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Conflicting results in DF and ADF tests
I am conducting unit root tests on the globtemp dataset, which is clearly a series with a trend and some seasonality (not stationary). However, when applying the ...
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Is power of a test lower bounded by the significance level? [duplicate]
Here's an example that makes me ask this question. Let the significance level be $\alpha$.
Suppose we have a normal distribution with a known standard deviation $\sigma = 1$.
$H_0$: The mean of the ...
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Head First Statistics Book: error in hypothesis test?
Chapter 13 in the book Head First Statistics deals with hypothesis testing. Its example is like the below:
A drug (called snorecull) cures snore at a rate, 0.9. Then, one gets
the below results.
...
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Statistical Tests for Model Selection in Nested Cross Validation?
I’m using nested cross-validation to evaluate multiple models and hyperparameter configurations. After running trials with different random seeds (outer: 3-fold with 10 seeds, inner: 5-fold with 50 ...
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How to test whether correcting an experimental response for a function of two controlled variables removes dependency on a controlled variable
I have an experimental setup in which I control two variables (x and y) and measure a third (z). I.e. a two factor response surface.
My hypothesis is that a function of x and y, f(x,y), better ...
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Hypothesis testing with unknown covariance matrix under the alternative hypothesis
I am trying to solve a binary hypothesis testing problem of the form:
$H_1 : \mathbf{y} = \theta \cdot \mathbf{x} + \mathbf{n}$
$H_0 : \mathbf{y} = \mathbf{n}$
where $\theta \in \mathbb{R}$ under $H_1$...
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Why is a pooled mean necessary in bootstrapping the difference in means?
Formulated Question
In a two-sample bootstrap procedure for testing the difference in means, why is it insufficient to subtract the group-specific mean from each bootstrapped observation (centering ...
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Wilcoxon signed-rank test always finding randomly generated ratios to be different from unity?
I need to test if a group of ratios from an experiment (calculated as condition1/condition2 from paired samples) is significantly different from one. All measures in the experiment are positive, real ...
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Do we reject null if we have a pvalue of 0.0503 at alpha = 0.05? What way to validate the rejection, if ever?
I know it is more than 0.05, but I'm just wondering since rounding it to two decimals will give 0.05. I just wanted to ensure I am not falsely accepting the null hypothesis. Is there any way to say ...
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What level of statistical significance to choose for test of equaility of seemingly unrelated regression coefficients?
It is possible to compare effects from models estimated as seemingly unrelated [1] [2] [3]. DVs may be related, IVs may be related, or both may be true. In any event, analysts test for equality of ...
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Finding outliers in mostly zero data
Background
I'm working on an algorithm to find a short pieces of DNA sequence in a long DNA sequence. I won't go in detail of how it actually works, but let me more formally state it to provide ...
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Standard error is too small on "perfect" data
While studying linear regression, I encountered this weird situation.
I am fitting a data to a linear model $\beta_0 + \beta_1 x$, and running a Wald test to check if $H_0: \beta_0 = 0$. Here is a ...
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Test (quantify) the association between categorical and numerical variable in survey data
I've just started working with survey data and I want to test independence between a numerical variable and a categorical one.
I've heard of weighted ANOVA, but how can I test the normality and ...
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Im confused as to how the calculations in finding a most powerful test and a UMP differs [closed]
I know that for a simple hypothesis to get a MP, You take the ratio of likelihoods by the NP lemma but I'm not sure as to how this extends to UMP and how the calculations would differ
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Doing "maximum p-value estimation" instead of maximum likelihood
Whenever we do maximum likelihood estimation, we look for the parameters that maximize the probability density of the data. On the other hand, when we compute p-values, we look at the tail probability ...
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Updating a Continuous CDF After Observing Realised Draw From Same CDF
I am trying to solve for some updated distributions, but having a little trouble conceptualizing what I am doing.
In particular, suppose I have two CDFs, say $U[0,0.8]$ and $U[0.2,1]$; call them $...
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Model comparison on data with Cauchy distribution
I am interested in determining the dependence of a state's position in density space, n, on magnetic field. With the magnetic field kept fixed, the presence of the state is measured by an increase in ...
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No significance in omnibus test, but significant in EMM [duplicate]
I am trying to investigate the difference between the level of a protein in people with and without an injury.
The protein is a transformed variable, and normally distributed. I wanted to adjust for ...
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Need help F-statistics requirment
I was working on the thesis and was stuck in the F test, I used a probability value of 0.05 or 5% before but my test results were not enough or exceeded the conditions. Now I want to try using a ...
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How to test for equal variances of correlated observations?
Let $r$ be a vector valued random variable with mean zero and variance $\Omega$.
Let $r_t$ denote a specific observation of $r$ at time $t$.
$\Omega$ is unknown but I have 2 estimates of it: $\Omega_a$...
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How to compare groups, while accounting for daily fluctuations in all groups?
There is this new technology to obtain and store heat from surface water:
In summer, a machine pumps heated water from a lake against a heat exchanger. The heat is transferred to an underground water ...
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