Questions tagged [hypothesis-testing]

Hypothesis testing assesses whether data are inconsistent with a given hypothesis rather than being an effect of random fluctuations.

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Peacock Test Implementation in R [on hold]

I have two empirical distribution (without access to the observations themselves). So, in order to see if the empirical distributions are "significantly" different, I took two large random samples ...
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Is this an example of a T-statistic?

Excerpt from a study https://www.researchgate.net/publication/328838624_No_More_FOMO_Limiting_Social_Media_Decreases_Loneliness_and_Depression: Although not every subject complied perfectly with ...
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two sample analysis with outliers

I've got some data from two groups which have different sample size. (univariate variable like 'price', and want to test whether they have significance difference ) The sample size of 'A' is 10,000 ...
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Hypothesis testing based on the concentrations of two cigarettes' samples

A cigarette producer sent two samples, one for each laboratory, which he thinks to be identical. The laboratories determined the concentration (in mg) of nicotine in each sample and they obtained the ...
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Hypothesis testing and p-value: a problem involving concept understanding [duplicate]

Consider the random sample $X_{i}$, $i\in\{1,2,\ldots,n\}$ such that $X\sim\mathcal{N}(\mu,\sigma^{2})$ where $\mu$ and $\sigma^{2}$ are unknown. Consider as well the following hypothesis whose ...
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1answer
59 views

How likely is sample A and sample B is from distribution C? [on hold]

Let's say I have a sample A: [0,0,0,1] and another sample B: [2,0,5,10,100,3,2,6] I would like to know the probability that A and B are both picked from the same population C. I tried applying a ...
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1answer
39 views

How to check if means and variances are normally distributed?

From here I read that The t-test assumes that the means of the different samples are normally distributed; it does not assume that the population is normally distributed. By the central limit ...
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Comparing survival times in overlapping groups

I have a following statistical setup I don't know how to attack: I have two therapies: say A and B. For some patients A works better, for other B works better. I want to direct patients to their ...
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Comparing heteroscedastic groups with sample sizes from 1 to 24… No valid tests?

I'm comparing 1 continuous variable across 36 groups (nurses grouped into 36 hospital units). Several groups have only 1 observation, but most have more, ranging from 1-24 observations per group. ...
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1answer
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Relationship between Mann-Kendall and Kendall Tau-b

Do the Mann-Kendall and Kendall Tau-b use very similar test statistics? It seems that everytime I perform both tests, they always provide the same p-value and same conclusion.
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2answers
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Statistical significance of binomial variable when sample sizes are different?

Suppose we have two groups of students given the same difficult test. However, one group of students was given an extra training session before the test. normal students = 123 students with extra ...
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Is learning how to do deep learning and machine learning actually harder than learning how to do regression (lm, nlme), t-tests, classical statistics? [on hold]

It seems like because most people are still using regression like logits or covariance pattern models and the work of Ronald Fisher to solve problems and machine learning is less popularly used, is ...
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Hypothesis test for pixel matrix equivalence

I'm going through this tutorial and I'm reworking it in R and I was able to do so. I tried to extend this tutorial by thinking of ways to objectively detect differences in images; e.g., can I run a ...
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4answers
79 views

What test do I use to check if two samples came from different population?

I'm aware that t-test checks if two sample data sets have the same difference in means with confidence. But testing difference in means is not equivalent to testing if the two distributions came from ...
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What is the correct statistical test?

I'm despaired about planning the evaluation of my experiment for my bachelor thesis and urgently need help with the selection of statistical tests. Brief outline: I want to transfer the mood ...
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9 views

Reporting difference in distributions for text

I am working on a problem that can be translated to determining which of two corpora generated a given sample text. I have a hypothesis for before some processing and other for after processing, and ...
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Is chi squared test of independence correct with control group?

I'm analyzing some data from an experiment in which passage of time between conflicting tasks is my independent variable and one of my dependent variables is a dichotomous one ("A","B"). I also have a ...
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Implementation of Hypothesis test on R² for regressions in cross-sectional setup

I am confused by the paper of Kan et al. (2013 - "Pricing Model Performance and the Two-Pass Cross-Sectional Regression Methodology") which proposes the execution of hypothesis tests on R² of ...
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Hypothesis Testing : To Test the presence of Seasonality Given the Seasonal Indices

I was just looking at this tool by Professor Hossein Arsham to check for the presence of seasonality in the data using seasonal indices. https://home.ubalt.edu/ntsbarsh/Business-stat/otherapplets/...
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Statistical test to measure whether certain candidates progress further in a job application process

If I have an interview process where people are phone screened, then if they pass then are moved unto another stage, and then another stage etc until they get an offer. I want to identify the ...
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Is this a sign of a bad IRT implementation?

This data is from the Indonesian UTBK SBMPTN (a university entrance exam). It is said to use Item Response Theory for scoring. I found something interesting about it. The image below shows the ...
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Using the $Z$-test instead of the binomial test for small $n$ - effect on power and Type I error

Setup Let $M \sim \text{Bin}(p,n)$. Let us then state the following two hypotheses: $$\begin{align} H_0: p = 0.5 \text{ vs } H_1: p > 0.5 \end{align}$$ To test these hypotheses, I could use the ...
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1answer
35 views

Apply normal or not-normal test to heterogeneously normal data sub-sets

I have a dataset made by measuring something on standard dilutions ranging from let's say 10, 100, 1000 and 10000. I checked how the results are distributed with the Shapiro-Wilk test, and it turns ...
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2answers
38 views

Clarification on equal variance vs unequal variance t-test

In unequal variance t-test (Welch t-test): $$H_0 = \text{No difference in means, but variance can differ}$$ $$H_1 = \text{Two sample means are significantly different}$$ I don't see the point of ...
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35 views

Using Chi-Square-Test for single item likert type hypothesis testing?

I conducted a Survey to find reasons why firms invest in a specific asset. I asked them in a Likert-question if different aspects are a reason to invest in [asset]. The Response for each aspect can be:...
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Why is the population standard deviation approximated as the sample standard deviation?

This question addresses calculating a p value from the mean and standard deviation statistics of a sample. I understand that the -general- philosophy is to divide the sample standard deviation by the ...
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games-howell test with multiple independent variables

my data doesn't meet the homogeneity of variances criterium. After a welch one way test I wanted to perform a post hoc games-howell test since it doesn't require the homogeneity of variances criterium....
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2answers
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Which statistical significance test should I use to solve this?

Which statistical significance test can i use. all are binary outcomes. Here is my table. I would like to know if there is a significant difference in mortality between the two groups (kidney injury ...
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1answer
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Mean Estimation from 1 Sample that gives Mean and Standard Deviation

The title didn't feel right to me either, but here is my problem: I am attempting to estimate the mean of lead concentration using a handheld x-ray gun, which takes a measurement at a point on the ...
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2answers
16 views

What is the proper test for sparse binomial data?

I'd like to preface this by saying I am a statistics newbie. I have a single sample from a binomial distribution of some experiment. The exact numbers are: Yes: 1 No: 45 I'd like to determine (1) ...
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A/B testing for control and test stores

I have historical data for 1000 stores across US. Now I want to introduce an offer in few of the stores (eg 20 Stores) and see its effect on overall sales of those stores after two months. The way I ...
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1answer
24 views

t-test on the difference of two independent observations

I want to check if there is any significant difference in my two sets of observations (which are not dependent). Now my first observations have two stages stag1_before and stage2_after same is with ...
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WALD test for risk ratio/odds ratio

Can I perform a WALD test for the log transformed risk ratio? I have calculated the null log risk ratio and the risk ratio from data. Can I use these two values along with variance of log risk ratio ...
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Method to detect statistical differences between populations [closed]

I would like to detect if two populations are the same between two time points and given several attributes. Imagine a population at day 1, with these characteristics: ...
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Hypothesis test of distributions from two biased samples using NPMLEs

Suppose $X_1, ..., X_n$ is a biased sample (bias mechanism known) from distribution function $F_1$ and suppose $Y_1, ..., Y_m$ is another set of observations sampled in a differently known biased ...
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Weird thing: The larger my lags, the smaller my Ljung Box test p-values

I am doing analysis to a dataset about U.S. Imports of Goods by Customs Basis from China. I deleted the data of the first 5 years, logged the data, and then decomposed it (or ...
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How to write the log likelihood for a full model of a negative binomial distribution

I would like to know how to write the log likelihood for a full model of a negative binomial distribution to test a null hypothesis that population mean group1 = population mean group2 vs not equal (i....
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Significance test for Patient Years

Previously, I had a question about CI for Patient-Years (py) and there was a great answer from @TamasFerenci. Now I need to find out the $p$ value for the py of two different groups. I have a table ...
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Hypothesis Testing: “Confidence Interval” Nomenclature

I am fairly happy with the concept of confidence interval. In a very basic guise we have a certain level of confidence that a statistic, say the population mean of a random variable, lies in an ...
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What is the relation between the effect size and correlation?

Correlation refers to the degree to which a pair of variables is linearly related. The effect size quantifies some difference between two groups (e.g. the difference between the means of two datasets)....
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Testing exam results

Given five exams per student (three oral presentations, two essay based) and between 14 and 24 students per course. Over eight courses the average scores are calculated. The last three courses, ...
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42 views

Is there a way of evaluating the quality of the result of a statistical test? [on hold]

Is there a way of evaluating the quality of the result of a statistical test, depending on the representativeness of a sample (or dataset) with respect to the whole population? For example, suppose ...
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3answers
95 views

How to calculate a confidence interval for a series of Bernoulli Trials?

I have to test if a event have a p probability of happening. I can run this event as much times I like (given it can be run by a computer). So I was searching a way ...
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Likelihood Ratio test problem

Consider a random $X_1,X_2, . . $ sample from $N(\mu,\sigma^2)$ Construct a likelihood ratio test for the following cases, taking $ \alpha=0.05$ a.) $H_0 : \sigma^2 < 4 $ v/s $H_1 : \sigma^...
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1answer
25 views

Advantage of the Gail-Simon Test (qualitative/ crossover interaction test)

It is common to use products of original variables as the basis of testing whether interaction is present. In regression analysis, for example, we can include both main effects and the interaction and ...
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4answers
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Why is the concept of the Null hypothesis associated with the student's t distribution?

There are dozens of continuous probability distributions like Gaussian (normal), Variance-gamma, Holtsmark, etc. Yet, the concept of the Null hypothesis is basically associated with Student's t-...
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What to bootstrap for hypothesis testing

I have a small question about the concept behind hypothesis testing using bootstrap. Assume that I need to evaluate two independent population mean differences: population a and population b. My doubt ...
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How to model negative, neutral and positive sentiment

I am wondering how best to model sentiment with three categories: negative, neutral and positive. Negative sentiment is represented with a value of -1 Neutral sentiment is represented with a value ...
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Switching $H_0$ and $H_1$ by replacing $p$ with $1 - p$

I was reading the source code of tseries::adf.test, and it writes ...
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Leave-One-Out Property (LOOP)

I was reading this paper, and I was looking at the leave-one-out property that they mention in Appendix B. The property is as follows: For $x\in \mathbb{R}^n$, define $x_i$ to be the $i$th element ...