Questions tagged [paired-data]
Paired data arise when an experimental or observational study design deliberately samples two units as a dyad to form a basis of comparison. Use this tag for any question about paired data or their analysis.
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Change paired t test to LMM: while the content tested before and after treatment is different
I'm new to linear mixed model. I'm not sure how to use it if the contents of pre and post test are different.
It's a within-participant design, including two sessions (with treatment and without ...
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How to compare variables with data from multiple experiments?
I have an experiment in which i compare the amount of attached bacteria in three different conditions. I have repeated this experimented three times, so now i have three datasets with the same data (...
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Are my data paired or not paired for a t-test?
I am analyzing data where my experimental design is as follows:
DNA and RNA samples were taken from 3 mesocosms at seven time points across the duration of the study to see DNA and RNA decay across ...
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Kruskal-Wallis versus Friedman - Paired data, but not repeated measures/blocks?
I'm trying to compare the difference in behaviour of an animal with no enrichment to the same animal with two (or more) types of enrichment. (Total active behaviours before/total active behaviours ...
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Identifying statistical significance of improvement due to treatment
Consider an experimental setting where the universe of elements (eg. webpages) to measure $U$ are split randomly into two equal sized groups, a control group $C$, and an experimental treatment group $...
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Which test can I use for comparing two reaction times taken from the same group that are not normally distributed? Instead of paired sample t-test?
I will conduct a study in which I compare the reaction times (acceptability judgement) to two different types of sentence.
I am assuming that scores will be normally distributed and I will use paired ...
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Compare Paired Data from 2 Timeframes of Different Lengths
I need to compare dependent samples (matched-pairs) from the same group in 2 time frames, simply a hypothesis test to determine if there is any statistically significant difference pre and post an ...
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How to form the hypothesis and which statistical test to use when we have before-after data of two individual groups?
So basically I have medical data where the data is collected from two different treatment groups and various variables are measured for individuals in the two groups. Data was measured before, during, ...
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Account for different amount of observations per participants without using a regression approach?
I am trying to figure out the statistics of a study where I have 60 participants with varying amounts of observation per participant. I am measuring facial muscle activity after a button press over a ...
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Jonckheere-Terpstra test for DEPENDENT samples with an ordered alternative hypothesis
I have a question about the tests that consider an a priori ordering (the alternative hypothesis is ordered - testing the hypothesis u1 ≤ u2 ≤ ... ≤ un). We want to compare a variable in the same ...
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Paired t-test vs two-sample t-test - animal populations
From my understanding, a paired t-test is used when samples are dependent of each other.
I'm having trouble deciding whether a paired t-test should be used when comparing the average population of a ...
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2x2 contingency table with some data-points paired and some independent
There are two items in a task (item A, item B). On each of the two items participant can score success (1), failure (0), or not provide a meaningful answer (NA). Participants with NA on both item are ...
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3 Paired Datasets Hypothesis testing
n = 72 subjects were randomised to 3 treatment groups: A, B, C, such that n = 26 for Group A, n = 29 for Group B, n = 17 for Group C. Measurements were taken before and after treatmentThe differences ...
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hypothesis testing depending on the distribution of the data
I have a paired dataset where the before-treatment observations are non-normally distributed (Shapiro-Wilk test p-value = 0.007) and the after-treatment observations are normally distributed (Shapiro-...
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What statistical test / analysis should I use?
I have conducted a RCT with two arm treatment. I would like to compare the difference on an 8 question pain scale between groups. Data has been completed at baseline and every week for 5 or 6 weeks ...
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Should paired data correlate when using paired samples t test?
I have repeated measurements from a usability study on 2 different interfaces (n=23). Since the difference between the measurements seems to be normally distributed I used paired samples t-test to ...
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Meta-analysing impact of Covid pandemic on risk for perforated appendicitis
I am analyzing the impact of the change in the management of appendicitis during the covid pandemic. I have paired data from 31 reports comparing the number of operations for perforated and ...
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Compare paired before and after composition proportions
I have some data on the composition of purchases by households, before and after an intervention. This composition is known at the number of items or amount spent level within 7 categories, and can be ...
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Wilcoxon Signed Ranks Test for relative differences
Is it correct to use the Wilcoxon signed ranks test for relative differences $\frac{Wx-Wy}{Wy}$, instead of absolute differences $Wx-Wy$? In some cases the relative difference is more relevant, for ...
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Comparing relative differences using paired samples t-test
I have the following problem:
I have data from a small usability testing session where participants (n=22) had to perform the same task on the original and a modified interface. I have to compare data ...
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Statistical test to compare between two groups when dealing with paired data
I am looking for an appropriate statistical test to compare numerical features between two groups when I have paired samples. I have two samples per subject (1 from tissue type 1 and another from ...
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How to find p-value for numeric paired variables
I am comparing student exam score and happiness. For example, a student with a 98 on an exam rated their happiness a '9' on a scale of 1-10, and 200 student did the same thing. I am trying to find the ...
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What kind of significance tests can I apply on before/after data that involves proportions?
I am trying to determine whether there is statistical significance from two groups of data. I have the data in terms of counts and proportions or percentages.
There are two columns which show the ...
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Is there such a thing as a paired-samples F-test?
I have paired data (from a pre/post-test) for which I assume that the variance differs between groups (again between pre/post). Visually, this assumption appears to check out and there is less ...
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effect size for pairwise permutation
I am reading a paper that is using permutations to compare the means of two different treatment groups (a nutrition study, took minimum - maximum) that have low sample sizes, and so the groups are ...
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How to run a paired permutation test for 1 classifier, with 2 sets of predictions (paired), with classification accuracies as the test statistic?
CORE QUESTION:
I have a single trained classifier (single participant) tested on 2 related multiclass classification tasks. As each trial of the classification tasks are related, the 2 sets of ...
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Paired T-test when within a group there is also dependence?
As I understand with paired T-test you have two groups and there is dependence between observations of these groups but within the group, there is no dependence.
How to correct for dependence within ...
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How to get rid of a nuisance parameter when the two parameters are multiplied
I have the distribution of a sample statistics which is given by a noncentral t distribution. This distribution is dependent on the population correlation ($\rho$) which is unknown. However I have the ...
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Distribution of the ratio of two related chi-square variates
Suppose a binormal population $X_1, X_2 \sim \mathcal{N}(0,\Sigma)$ where $\Sigma$ is obtained from $\sigma^2$ the variance of each item, assumed equal, and $\rho$, the correlation between pairs. We ...
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Need the equivalent of a "paired T-test" for percentages (test-retest comparison between groups)
I have an observational study with a control group and a treatment group (n=25). All the subjects are given the same test (which consists of 9 questions, each of which has 4 multiple choice answers). ...
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How do I test the significance of factors on a time series dependant data set?
I am working on a dataset where a new administrator joins a school, and I want to see if it affects the number of students at the school. There are also characteristics of the administrator (age, ...
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Pitfalls using ratio of mean change to standard deviation of change - i.e. longitudinal MSDR
A number of biostatistics papers use the mean-to-standard-deviation ratio (MSDR) of change to summarise symptomatic progression on various clinical assessment scales. This is done to compare disease ...
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Visualize multiple 2 sample t-tests
First time on cross validated - so if my question is not clear enough, please let me know.
I have 2 groups of websites - experimental and control. Each of these groups has many float variables I ...
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Probability based on proportions from paired samples
Consider a dataset of partial pressure of oxygen (po2, in kPa) measured in paired arterial and venous blood samples from a population (n = 38251).
The distributions of both type of blood are displayed ...
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Best-Worst Scaling: ties and variance/confidence intervals
In a situation where the quality of a result computed by an algorithm is subjective, I would like to let users compare the results of different algorithms. It seems to me that the method of Best-Worst ...
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Paired Data Confidence Intervals For Accuracy
I had an individual take a test with 500 binary questions before and after an intervention. Let's say they scored an 80% initially and a 90% on the second pass through.
I can measure the absolute ...
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Comparing paired and unpaired samples
I have data from three groups of participants: Group 1, Group 2, and Group 3. Participants in Group 1 have their performance recorded on Task A and Task B. Participants in Group 2 have their ...
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Does Paired T-Test provide the same result as Wilcoxon Signed Rank Test on the same dataset?
In principle they are trying to test the differences in dependent data.
However, do they always provide the same outcome on the same dataset?
What happens if we get contradictory result by using both ...
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Wilson confidence interval for partially-paired data
I have a data set with paired observations (before and after a specific intervention). There are a lot of metrics in this data set, some of them numeric (of unknown distribution) and some of them ...
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Which statistical test should I use in my problem? (Permutation, Bootstrap, or some other test)
I have a dataset like this:
H_0: The Test values are randomly generated.
H_A: The Test values are related to the True values.
...
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Testing difference of medians and stochastic ordering using paired samples
I have paired samples from skewed distributions with unequal variance (before and after treatment), and would like to test for
difference of means
difference of medians
stochastic ordering of treated ...
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How can I determine the significance of two sets of paired, independent measurements?
Let's assume I am trying to find out whether individual people are better at beer pong while sober or drunk. In this experiment I do four trials. On Monday, I first have them throw 100 times sober and ...
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Is there a statistical test that can be used to see whether health rates have changed between years and locations?
I am having a difficult time deciding how to go about this. I thought a T-Test would work, but I am not 100% sure. I have two sets of data. One contains a rate for diabetes in a town in a single year. ...
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Is 90% of the use of paired signed-rank Wilcoxon test incorrect due to violated distributional assumption of symmetry, or is it more general?
Everywhere, including forums - also this one, handbooks of statistical tests discussions, I can read that the paired Wilcoxon test does require the assumption of symmetry.
This would mean, that:
Most ...
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Comparing two groups, consisting of same population
Suppose I have a sample population. I define obesity by three definitions i.e. On basis of BMI, Body Fat % and Waist circumference. I apply these definitions to the whole population.
Now I have three ...
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Compare two stores in specific products price (Non-parametric model?)
I have two stores with products and prices, I want to check if there is a systematic difference in product prices between the two online stores?
I chose the Mann Whitney U test but how I can confirm ...
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Pre-study sample-pairing validity (two same-scaled IVs, binary DV)
Summary: is pairing samples ahead of time okay for testing? What test do you use given the resulting assumptions?
Overview
Goal: The goal is to determine which IV has a stronger influence on (...
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Model for comparing two ordinal dependent variables
I am trying to do a within subjects comparison of two 5-point Likert scale questions and seeing what influences the differences. I have a number of IV's (all categorical) that I used for ordinal ...
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Possible to use linear regression instead of paired t test?
I have participants who were measured two times. First, without any intervention. And second, with an intervention. Thus, I should use paired t-test as both measurements are normally distributed (...
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paired t-test for two different samples and measurements taken in two different years
I measured hourly temperatures of site A and site B in June 2016 and June 2017. I used paired t-test to compare the means of site A & B for June 2016 (n=720) and p-value was 0.07 (significance ...
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