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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Pairwise comparisons pre test post follow up
I have to complete my dissertation in a couple of days. I am proposing a RCT with two independent variables: treatment( group 1 : avatar cognitive therapy , group 2: CT) and time(pre-test, post-test ...
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1answer
20 views
How to plot paired data that has small deviations?
I am showing that applying a certain method leads to improved performance on a machine learning problem, and that this effect is consistent across different datasets (in this case, datasets collected ...
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1answer
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Independent or matched groups?
A very beginner level question here: I'm trying to see whether there is a difference in how students assess the usefulness of 5 possible courses to be added to their curriculum. Each student was asked ...
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Bayes factors in R for correlated proportions (such as a “Bayesian McNemar's test”)
Is there any way to get Bayes factors in R for correlated proportions (i.e., paired sample)?
For example, the same group of 90 people is measured with one technique, then with another; once there are ...
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3 views
Comparing which histogram has overall low cost
Let's say there are two histograms which basically is constructed from array of numbers which is measured by, repeatedly performing a task by two different methods and individual numbers are time ...
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3answers
194 views
Paired t-test means that the variances of the 2 samples are the same?
Do paired samples imply that they have the same variance?
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Scale invariant comparisons of two sets of vectors
I am dealing with the following problem.
Let A and B represent two sets of real-valued vectors. The vectors are of the same dimension, yet the sets contain different number of vectors.
I am looking ...
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13 views
Potential problem in using paired t-test or Wilcoxon if the two samples consist of multiple draws from same group?
I have an experiment that works loosely works as follows:
There are ten subjects in each treatment. There are two treatments, A and B. Each treatment has 8 rounds. In each round, each subject is ...
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14 views
Proper analysis procedure of paired rate comparisons - ratio or difference?
I have a set of population counts where each row represents a different region, and variables show overall counts and counts/percentages within specific groups/criteria. I am interested in the cross-...
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1answer
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Is my interpretation for Wilcoxon Signed Rank test correct?
I ran a wilcoxon signed rank test on paired samples where the outcome variable was a test score. The samples were paired by as siblings (younger and older sibling). I have a problem interpreting the ...
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1answer
19 views
How does Normal approximation work when ties exist for Wilcoxon Signed rank test?
I ran wilcox.test() in R (outcome variable was a test score and the data was paired samples) and got a warning message saying that it cannot generate a p-value for tied values. I saw the R document ...
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24 views
Compare variables with zeta-score
Assume the calculation of a physical quantity $x$ from a given formula i.e. $$x=\dfrac{a*b}{c}$$ where $a, b$ and $c$ are experimental observables, therefore $x$ is a quantity derived from ...
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52 views
Statistical test for dependent data- comparing groups of pairs
I have a question about statistical tests for dependent data. This will sound a bit strange/extremely naive but pls bear with me- here is my problem formulation:
I have 500 individuals, and I'm ...
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14 views
how to report paired comparisons in linear basis function model?
I am struggling with correctly reporting the results of a linear (mixed) basis function model I ran. The model is specified in R as
...
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18 views
Using a paired t-test on panel data
I am working with a data set containing approximately 100 students who have all been tested before and after and intervention. I am now going to test whether the intervention has had any impact on the ...
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1answer
135 views
Paired or unpaired t-test and Wilcoxon signed rank test?
I am having a conceptual problem, of not being able to grasp whether my data is paired or unpaired. I have to test for the mean and median differences between two sets of data: SBP and GICS (see ...
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Linear model for paired data [closed]
We have 100 subjects of varying and known age and sex with two strongly related dependent variables (X, Z) measured with two methods (A and B). Method B is known and expected to show more reduced ...
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1answer
17 views
Logistic regression: Sample size for emmeans comparisons
I conducted a logistic regression with a 3-levels categorical predictor in SPSS using the GENLIN procedure. As I am interested in the pairwise comparisons between all three predictor levels, I used ...
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1answer
38 views
One tailed paired t-test
Ok, this might be an obvious question but it's had me stumped.
Let's say we're doing a test to see the improvement on test scores before and after some process.
We could state the hypothesis as:
H0:...
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Wilcoxon rank signed test, paired or non-paired test?
I have been trying to figure out, whether or not I should use a paired or a non-paired test. My question comes from the fact, that I am trying to get the pseudo median, in order to say that SBP is [x] ...
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Comparison of paired count data between two treatment periods with different length of follow-up
I am currently using SAS 9.4 to carry out a retrospective analysis of patients who switched from drug A to drug B. I am interested in assessing the hospitalization counts before and after switch to ...
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2answers
25 views
SPSS Paired Samples T-Test outcome interpretation
Hypothesis:
-Blood pressure will decrease after intervention
Results (blood pressure):
Systolic bp before mean: 102.00
Systolic bp after mean: 97.10
Diastolic bp before mean: 70.80
...
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1answer
38 views
What SPSS test should I use for blood pressure pre- and post-intervention for comparison?
I have 10 participants who consumed an intervention for 3 weeks.
I would like to look at any significance between pre-intervention and post-intervention readings.
What SPSS test should I use?
I ...
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8 views
Paired samples with various ordering in observations, signed rank test?
I have a small number (10) of samples to analyze
The idea is to measure the impact of two surgical procedures, A and B.
In my population, I have people who did first A, and then B, and other people ...
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18 views
paired t test to compare means of proportions
I have 12 subjects.
One Indipendent variable: word learning (2 levels: learned/not_learned)
One Dependent variable: proportion of sound exemplars in the language heard by subjects (proportion ...
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40 views
Wilcoxon Test gives W=0
I am running the Wilcoxon Test on my data, however, I get a W value =0. My questions are two: 1): Why is the case such a test gives 0? ii): How to interpret such results?
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Wilcoxon signed-rank test for paired and repeated measures data
I have a dataset with 45 participants, each with 1-7 datapoints/observations (126 total observations). Each of these observations represents a window of time in which two different methods attempt to ...
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1answer
72 views
How to run paired t-test when number of control and treated experiments aren't the same?
I'm working in a biology lab and I treat some cells with a drug (treatment) or untreated (control), then transplant them into mice. Each experiment starts with the same cells (being exposed to the ...
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Pursuing meaningful questions about pre- post- intervention outcome measures in single condition treatment
If you are not fortunate enough to have a control group and have a single condition only, what meaningful questions can you ask about the change in pre to post intervention scores?
If ANOVA or ANCOVA ...
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0answers
25 views
Paired $t$-test with multiple values
With the following data, I believe the difference in performance between two athletes can be measured with a (one- or two-sided) paired $t$-test:
...
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18 views
Paired Wilcoxon signed rank test-compare median
I have been comparing driving behavior before and after a technological intervention for a specific group of people. My data is far from normal hence I have used paired Wilcoxon signed rank test.
If ...
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0answers
59 views
Can a Wilcoxon signed rank test be applied on dated data?
I have data for military male and female orders for types of clothing purchased from 2012 to 2018 (below is a very simple example - most of the data is one item purchases). If I look at one type of ...
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44 views
Permutation tests for paired data with several variables
I am trying to answer my own previous question, with a permutation method.
I have a reference method $M_{ref}$ that I would like to compare with other methods $M_1$, $M_2$, $M_3$ when taking ...
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1answer
27 views
Paired variables?
In our research on apprenticeships in early modern times, we have a series of observations (cases), each with several variables. Each observation is unique because of its combination of the variables "...
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1answer
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Are there any statistical tests or measures for paired data with more than two groups?
Are there any statistical tests or measures for paired data with more than two groups? My dependent variable is pretty flexible, but I'd really like to have five independent variables compared ...
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26 views
How many pairwise combinations is possible?
I have a dataset regarding a natural language problem that am tackling with machine learning. My goal here is the generate training samples for one of the classes. I do this by doing pairwise ...
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27 views
how to combine Paried t test and multilevel regression in R
I want to compare the difference between two conditions (fed or fasting) for 15 participants, but I have two runs for each participant. I can average the two runs for each participant and do a paired ...
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Algebraic Manipulations in Mann-Whitney-Wilcoxon Test Statistics
Given
Let $\Delta > 0 $ be positive real number. Consider the Wilcoxon-Mann-Whitney upper tail test $H_0: \Delta \leq 0 \,\,\, \text{vs} \,\,\, H_a: \Delta > 0$ aimed at testing the difference ...
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2answers
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Trying to do a paired t-test but one variable is not normally distributed, log transformation did not work
I am trying to do a paired t-test but one of the variables is not normally distributed (vegetarian enhanced), as you can see from the boxplot.
I tried to do a log transformation but it made the p ...
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2answers
63 views
How do you perform Wilcoxon matched-pair sign-rank test in Stata using a grouping variable? [closed]
I'm performing a diagnostic method comparison study in which I have 2 groups; one assessed using the experimental method, and one assessed using the standard method. These groups are matched, with 3 ...
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1answer
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Help with calculating number of animals for a fetal surgery experiment
Rather odd question. I'm a surgical resident who is currently a research fellow in a lab studying fetal surgery. Our plan is to test a glue which we believe will help seal a uterus after we open it to ...
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88 views
Proof that the pooled sample variance is biased when paired comparison is not used when it should be
Given the model for what is meant to be a paired comparison design:
$y_{ij} = \mu_i + \beta_j + \epsilon_{ij}$
$i = 1,2; j= 1, 2, ..., 10$
Eg. An experiment comparing the different in mean hardness ...
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0answers
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Comparing 3 groups at 2 time periods
I'm analysing a dataset and comparing three zones at two points in time. The data in question is:
Hourly sightings of wild fish (CPUE)
In one of three adjacent zones (A, B, and C)
During the ...
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64 views
Applying Cliff's delta to paired data
Wikipedia provides a few ways of calculating Cliff's delta - an effect size quantifying distributional shift. However it only talks about having 2 samples that are unpaired. While one can apply the ...
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Comparing changes in pre-post count results for two cohorts
Thanks in advance!
I have a pre-post analysis Of cases and controls. The outcome variables of interest are emergency room visits and hospitalization visits - both rare occurrences with median = 0 ...
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2answers
24 views
Clustering for pair-wise data
I have been looking for algorithms in Python to create clusters from pairs of data. The data structure is similar to the stackoverflow post: An algorithm to create clusters from data pairs in python, ...
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2answers
124 views
Should I use a paired sample t-test to compare two methods of measuring absorption lines?
Background
I'm doing a research project in astronomy and measuring equivalent widths of absorption lines using Gaussian fits from a star's spectrum in order to determine the star's chemical ...
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Comparing survival rates
The question I have is focused on comparing remission rates at a fixed point in time.
For example, I have cancer type A and cancer type B (the two are not mutually exclusive groups) and all patients ...
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1answer
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Which statistical test to use? Not really paired, not entirely unpaired
I am setting up an experiment where I would like to determine whether there exists a difference between the participants' average self reported mental effort in some condition A and condition B.
The ...
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37 views
Regression on a change between a variable before and after?
In my dissertation I am using a paired sample t test to see if there is a statistically significant difference between consumers' intention to purchase from and attitudes towards purchasing from a ...
