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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Testing positive relationship with multiple predictors

For a research project I am working on I am trying to determine if there is a positive relationship between two predictors and a response. My current model is: Salary = B0 + B1 Cost + B2 SchoolType + ...
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Sample size estimation for linear regression with repeated measurements

i'm in a bit of a pickle. I have a quantity y that I want to estimate from a measurement x, via linear regression. Per data point, i can repeat n-times the measurement of x, e.g. to get a better ...
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I need to think about the best model to use for the below problem and im unsure how to solve this question [closed]

In an estuarine habitat, researchers are interested in understanding how salinity affects the activity rate of a bivalve mollusc that plays an important role in sequestering nutrients from the water ...
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Correct use of Chi-square and hypothesis testing?

I have a dataset which contains lots of data on customers and their actions within their journey through our business, one of these actions is how many of our events they have attended, another action ...
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Independent Sample T-test or Mann-Whitney U test?

I am a very young stats learner, and I need help understanding the justification of a test choice. I have a sample of 39 participants (20 females and 19 males) been measured on task performance, and I ...
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Will a negative data value have impact on t-test?

I want to test the significant difference between two data sets via t-test. control group = 2 observations Treatment group = 2 observations Sample replicate-1 replicate-2 control 41.043 -38.567 ...
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ks test for uniform distribution

My question is similar to this post (KS test for Uniformity). KS p-valuse changes when samples are in different position, even if they have the same intervals. For example: ks.test(c(1,2,3),"...
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Standard convention for test statistic for F-test?

According to my textbook, Mathematical Statistics with Applications 7th. Ed, they write the test statistic in a F-test, that compares variances of two different populations, so that the larger ...
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Question regarding asymptotic assumptions and hypotesis testing paradox for large samples

Suppose we would like to verify if a r.v $X$ follows a distribution with cumulative density as $F$, if $n$ goes to $\infty$ I'm able to use komogorov test which states reject $H_0$ (stating that $X$ ...
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Contradictory test results

My question is relatively simple, and has to do with reporting seemingly contradictory results from statistical tests. This is the problem. There are two independent groups, and two research questions ...
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Represent rejection region using p-value

Let's say we have some level $\alpha$ test (more precisely, family of tests parametrized by $\alpha \in (0,1)$), $\delta(\mathbf{x},\alpha)$. This means $$\sup_{\theta \in \Theta_0} P_\theta(\mathbf{X}...
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What type of test to use for comparing frequency

What type of test to use I’m in college doing a project for my stat class. I have chosen for the project to test my hypothesis that truck sales have increased compared to cars in recent years. For my ...
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p-value is missing from drop1 (R)

I have the following model model (R language). My goal model is Y~N*V but since this also happens for ...
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F and t test statistics for testing $\sum_{i=1}^t \lambda_i\alpha_i=d$ in one way anova

According to the book: Plane Answers to Complex Questions - The Theory of Linear Models by Ronald Christensen, for a linear model $$Y=X\beta+\epsilon$$ the test statistics for testing $H_0: \lambda' \...
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Analytics solutions for Textbook Publishers [closed]

I work in the education industry, and have access to the following information across a few hundred colleges in my country of residence, from the last 3 years. · The courses offered by the colleges ...
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Finding p-value in two-tailed F-test

Image and example come from "Mathematical Statistics with Applications 7th Ed". The test is done at the level alpha = 0.10. I am curious how they got a p-value of 0.2010, or rather how they ...
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What is the overall probability of two false results for the permutations of two binary tests

Graduate statistics was 30 years ago, I'm a bit rusty...Looking to determine the probably of all false results when taking two rapid covid tests (2 false positives, 2 false negatives, false negative/...
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To what degree should one trust significance of different analysis of the same data set done by different groups? [duplicate]

Suppose there is a data set $D$. There are 20 groups of researchers independently. Each group will publish a few results on this data set $D$. Suppose each of them find about 3 tests significant($5\%$ ...
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At what stage should we set the value of a significance level? And in what range?

There are at least three different recommendations regarding the location of the stage at which we should set the value of the significance level in the hypothesis testing procedure. In wikipedia ...
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How many tests can one do in a medical publication?

Suppose we are in the following setting. There are 10 covariates and 1 response along with some other data derived from those covariates. One can do regression of 10 covariates to 1 response to test ...
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What does it mean for a statistical test to be "robust"?

Is there an intuitive way of understanding what these two sentences mean and why they're true?: "ANOVA is 'robust' to deviations from normality with large samples", and... "ANOVA is '...
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Appropriate test to test for difference in mean (Likert scale)

I want to find out whether the mean of a certain variable (rating on a 5-point Likert scale) significantly differs from the midpoint of the scale, i.e. 3. My sample size is 48. I am wondering whether ...
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2x2 + 1 control condition testing

I have a somewhat unusual statistics question for you, which I'm currently despairing of, maybe you have a tip for me... My experimental setup (comparing two visualization techniques with/without gaze-...
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How can I define this restriction in R

545 observations of young working males in the U.S. with some professional and personal characteristics Variables are as follows: logwage: logarithm of per hour wage rate; union: dummy variable, 1 if ...
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UMP of a distribution

I need to find the UMP of a random sample $X_1,...X_n$ I know that the pdf of this problem is $$f(x;\theta)=\frac1\theta*x^{(1-\theta)/\theta}$$ where $$ \theta\in(0,1)$$ After some calculations i ...
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How do I use inferential statistics on Likert scale data?

I'm doing research for a class, and I'm collecting the following data: The background questions are my independent variables and the survey questions are my dependent variables. For the latter, I'm ...
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Understanding the difference between linear and interactive terms in Tukey HSD

I have an analysis of a dataset with a factorial design. Currently, I've been doing the analysis in R, using aov and TukeyHSD. I ...
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PICO statement vs hypothesis statement

I want to compare two operation types in a multivariable regression model. Operation type H is the most common one, and is the standard operation type for this type of injury (also the reference group ...
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T-Test (independent samples) alternative hypothesis [unequal means] is not significant, but alternative hypothesis [mean 1 < mean 2] is significant

I conducted a T-test to see if two independent groups (English (n=324) vs. German-speaking participants (n=346)) differ in their motivation to do activities for fun (Likert scale instrument). I use ...
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Titanic Dataset- Survival Probability (Combined effect of Gender, Age and PClass)

I have been assigned by my statistics sir to calculate survival probability of Passengers of Titanic by combined effect of Gender, Age and Passenger Class. I do not understand without Logistic ...
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Using software to apply tests under different perspectives (sets of hypotheses $(H_0, H_1)$)

I have read very useful paper "Wilcoxon-Mann-Whitney or t-test? On assumptions for hypothesis tests and multiple interpretations of decision rules" by Fay and Proschan (2010). This paper ...
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Need to identify correct confidence interval

A manufacturer of precision gaskets makes gaskets in two grades A and B. In A, the precision gaskets thickness is far more critical than in B. The production run for A is very small, whereas the ...
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Performing a MWD test in R

0 Hei, I would like to do a MWD test on a model to determine which one is best between a lin lin and a log lin to describe a model. I found than in R one can use the PE test from lmtest, but I find it ...
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Photo attractiveness rating experiment: significance and effect size

I'm a photographer working on a personal project where I experimentally test dating photo advice. I take photos of people under different conditions, changing one variable while keeping others ...
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How to deal with an imperfect reference standard in a comparison of two diagnostic methods?

Summary We discovered after performing our experiment that the method for determining our reference standard was not perfect: it may have a false-negative rate of up to 20%. With no way to confirm ...
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Best statistical approach for psychological experiment

I have done an experiment where I have two groups of patients that received different treatments (Group1 received treatment 1, Group 2 received treatment 2). I measured a value that should be ...
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Which hypothesis test to perform? [closed]

I’ve got a problem figuring out which hypothesis test to perform,how many to perform, AND how my null, and -alternative hypothesis should be articulated. The assignment: “The data set behind this ...
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Hypothesis testing with one tailed test

I have a model: $$Y=\beta_0+\beta_1x_1+\beta_2x_2+\beta_3X_3+\beta_4x_4$$ and I want to test these two hypotheses: $$H_0: \beta_1>-3 \qquad H_a: \beta_1<-3$$ So if I conduct a one-sided test at ...
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Interpretation of the Holm procedure

I have used the following code in Stata to calculate the p-values using the Holm method. However, I can't understand what to report and how to interpret these results. ...
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Legitimacy of transforming data before statistical tests

I have two groups of samples (N=4 for each) and found that there is one outlier for each group (both are higher than the rest of the respected samples within the groups). I have no resources to repeat ...
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Understanding the "multiple comparisons problem"

I am trying to understand the multiple comparisons problem based on the wikipedia article below: https://en.wikipedia.org/wiki/Multiple_comparisons_problem In this article they take the following ...
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What kind of parametric test to use to find difference in distribution for two Heteroskedastic sample?

I was analysing Titanic Dataset, and I have to answer this question: Is there a significant difference in Age distribution between those who survived and those who did not? Given: N1=865, N2=430 Both ...
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Is it reasonable to set the null hypothesis as the well-accept classic model?

Suppose that I did an experiment and collected a dataset. In previous literature these type of dataset are explained by a well-accepted model, called Model M. I believe that the Model M cannot explain ...
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Relationship between the t-statistic and F-statistic in simple linear regression

Consider the simple linear regression model $ y_i = \beta_0 + \beta_1{x_i} + \epsilon_i$ Suppose in an OLS, the $t$-statistic for the null hypothesis $\beta_1 = 0$ is $1.92$, what is the $F$-...
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Test if regression coefficients are equal between periods of time

I have multiple observations per year and I was asked to estimate an individual regression line for each year within a single model. My data has three years (1979, 1980 and 1981) and two independent ...
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How can I test if there are significant differences between four distributions?

Here is a graphical display of my data: The x-axis is categorical from 0-5 in terms of how many of a certain damage type are present on a leaf (with pink and blue bars representing the different ...
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Appropriate Statistical Test for Repeated Paired Data

I'm having trouble deciding the appropriate statistical test to use for a given experiment. 13 participants filled out a survey before and after variations of a treatment. Given the participant's ...
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Experimental Design for clinical trial

A clinical trial is to be carried out using four different therapies A, B, C and D. The effects of the therapies on tumour size are to be compared. Four patients are to be tested, one on each of the ...
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Comparison vs Reference Group, which tests to use in this scenario?

we are researching whether the date of a certain medical procedure impacts the complication rate of said procedure. To this end we have identified multiple risk factors we would like to study more ...
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Hypothesis testing two unfair coins to see if they have 'equal' bias [duplicate]

Consider tossing two unfair coins 100 times: How can I know using the two sets of Heads or Tail results whether the two coins have an equal (or similar) bias with a 95% confidence? I am currently ...

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