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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Can I conduct a paired t-test to compare regression coefficients?
I want to compare the regression coefficients for two variables from the same sample.
My models may look like this:
$$
\hat{Y}_1 = \alpha + \beta_1 * V_1 + \beta_2 * V_2\\
\hat{Y}_2 = \alpha + \beta_3 ...
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16 views
Comparing AUCs: Same Control, different Test Group - paired or unpaired? pROC
I want to compare two AUCs using a bootstraping method from pROC package (roc.test).
I have done a classification using Logistic Regression:
1. Cancer (high risk) vs. Control = AUC 1
2. Cancer (low ...
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0answers
20 views
Checking for consistency and selecting the best among multiple measurement techniques
I am tasked with comparing $N$ statistical analysis methods (where $N$ is relatively small, say $N=5$), possibly not independent, for estimating some quantities $X,Y,Z$ based on some given data. Each ...
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11 views
How to compare KM curves for paired data?
How can I use stratified log-rank test to compare survival curves for paired data?
I can't find any R package for this.
Thank you
0
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1answer
23 views
Paired t-test for different observed parameters - Should I use multiple compairaison's tetsing and how?
I have a group of rats that each go through two treatments: Control (No stimulation) and Laser stimulation.
For each treatment I obtain several number of parameters such as Attention score, number of ...
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0answers
10 views
Classification with paired data
I have a set of data with predictor $X_{i,j} \forall i \in [1,N], j \in [1,2]$ for $N$ paired items in 2 classes. The full distribution over $X_{i,j}$ is not informative of class identity; however, ...
0
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1answer
50 views
Focal Predictions from a linear model: How to test for difference between factor levels (pairwise) instead of comparing errorbars?
Sorry for the cluelessness, I know this is a topic that arises often in different variations. Still, I couldn't find an answer for my situation.
In my work, I sample people and try to generalize the ...
1
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1answer
42 views
There is very slight difference but also statistically significant. Could there be a mistake?
In my study to investigate the effect of filter glasses on reading speed and contrast senstivity in albino patients, there is little change in the reading performance level
n:61 patients
Reading ...
2
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1answer
20 views
What kind of test shall I use to test if the two data sets are significantly different?
The table below shows my example data set. I have 19 sentences (as an example). For each sentence, if word A is included it is recorded as 1; otherwise, it is recorded as 0 (shown in column A in the ...
1
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1answer
22 views
How to analyse association between two (paired) sets of measurements, when arbitrary to which set each member of a pair belongs
I have pairs of measurements and need advice to select a measure of association between the measurements. The special aspect that has me confused is the symmetry: there is no reason to allocate a ...
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0answers
15 views
Entropy of large sample $X$ and small sample $Y$ comparison
Distribution $X$ of a real continuous random variable is unimodal and slightly non-normal with $1,000$ observations.
Distribution $Y$ has the same characteristics (not perfectly identical in moments ...
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1answer
15 views
Paired T-test or Linear Mixed Model or what else?
I have measured 8 different features on the same mice on three different days. I want to compare the means of those 3 days based on the features.
I have executed paired T-tests for each feature in the ...
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0answers
10 views
Should I treat the samples as independent or paired for testing?
So, I am going over the statistical testing that was done by a former intern and checking whether anything can be improved. I am having some trouble with deciding whether the samples for the project ...
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0answers
11 views
Comparison of time series data sampled on alternating years
I have a dataset of values sampled yearly from 1968-2018. I need to compare all even year samples(as a time series) to odd year samples(as a time series) to determine:
if they do/do not follow the ...
2
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2answers
24 views
Statistically different change
I'm a statistics noob, and I understand this is a very simple question, but I didn't know what to search for to find an answer.
I have paired values for a variable (pre and post treatment) for two ...
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0answers
27 views
Interpret results from Mann Whitney pairwise hypothesis test in R
I have run ten runs of cross-validation in R for four models, and I have then computed an RMSE error measurement on each run of each model. First, I used ...
1
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1answer
69 views
Is it OK to use gls (Generalized Least Square) to analyze repeated data? What about the wrong degrees of freedom?
There are mainly 3 commonly used ways of analysing repeated observations via model: linear model via GLS estimation, generalized linear model via GEE estimation and mixed models (G)LMM.
Let's forget, ...
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0answers
15 views
Paired T-test for a population with positive and negative effects
I have before and after values where the treatment is expected to have a positive effect on a set of instances (I know what they ...
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0answers
13 views
Paired T test or some kind of ANOVA
I have measured left and right side bones of several whales. I want to know whether there is a difference between left and right sided bones. For this I have used a paired t-test. However, I also want ...
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1answer
22 views
Small paired samples comparison: which approach should I prefer?
I have the following small dataset, that consists of scores before and after a certain treatment for 15 individuals:
...
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0answers
18 views
how to test multiple models on the same data for significant differences
I have two sets of data that I am fitting 5 different regression model function types to: 2 polynomials, a power, an exponential, and a gaussian. I am using AIC scores to determine the best fit of the ...
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0answers
5 views
Transform 3 dependent samples (each n = 10) into 2 groups (n1 = 20, n2 = 10) - which statistical test?
I have 3 dependent measures of psychological data (each participant took part in 3 different conditions). I would like to add sample 1 and sample 2 together (because condition 1&2 are similar) and ...
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4 views
Is there a way to use Dunnett procedure to dependent, repeated data in a longitudinal experiment?
I have an experiment with 2 groups and subjects examined at subsequent times, t0 - called baseline - to t5. I would like to assess the changes from baseline and correct it for multiplicity. I know the ...
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0answers
8 views
How to compare treatment slopes in pre-post with 2 treatments?
I have a pre-post experiment. At t0 both groups start from a comparable values of some parameter. There are two treatments. Treatment A doesn't show improvement over time. Treatment B - does. In the ...
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0answers
9 views
Which confidence intervals should I report in a pre-post and longitudinal trial?
Let's assume the following scenarios:
Single group of subjects (1 within factor), 2 time points, pre and post. I report a confidence interval for the difference. That's simple.
Two groups of ...
0
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1answer
26 views
Is adding batches of samples to a non-stat sig sample p-hacking?
Here's my scenario. I take 1000 samples each from my control and treatment. I note that the difference in means is not statistically significant (stat-sig) under the null hypothesis testing. I then ...
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0answers
40 views
Comparing two absorption spectra as time series
I would like to compare two absorption spectra ( or interferograms) and conclude whether between these two there are statistically significant differences at particular wavelength intervals. At the ...
1
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1answer
43 views
Finding anomaly using statistical distributions [closed]
I am trying to find if a particular genre of books is more popular with people of a particular region of the world. I have data for the readership of a set of books of different genre corresponding to ...
8
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1answer
103 views
Distribution of the pooled variance in paired samples
Suppose a bivariate normal populations with means $\mu_1$ and $\mu_2$ and equal variance $\sigma^2$ but having a correlation of $\rho$.
Taking a paired sample, it is possible to compute the pooled ...
0
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1answer
32 views
Paired vs Unpaired t-Test basics
Hope this is not too basic:
I understand we used paired testing in situations where, e.g., the same subject is tracked before- and after- an experiment/treatment, e.g., before- and after patient ...
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0answers
13 views
What's the best metric to compare products that are defined by 2 parameters, where for both these parameters, lesser the value, better the product is?
Say the product is: house to buy. And, say, houses are defined by 2 parameters only:
A, which is popularity rank (which is a proxy for the demand), and
B, which is the price of the house
Obviously, ...
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0answers
22 views
Test for paired proportion data
I want to test for differences in the connectivity of two different brain regions (A and B) measured in 100 subjects. For each brain region, I have measured connectivity to 150 other brain regions (i....
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0answers
14 views
Statistical Significance In Sample Between Two Time Points
I have a set of time series data with one observation per week for each county in a certain state. I want to see if there is a statistical difference between the observations at the point in time ...
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0answers
24 views
Quantify the similarity between two sets of data
I have two sets of data y(x), one from experiments, and one from simulations. The datasets are naturally paired, as the same 80 different test set-ups were used for ...
2
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1answer
48 views
Paired t-test with à priori known variance for Model validation
We have a multiple linear regression model $y = f(x1, x2)$, which has been fitted with measurements of a designed experiment of the input variables $x1$ and $x2$. Based on the design, the complexity ...
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0answers
18 views
Paired t test: standard deviation of mean versus mean difference
I would be grateful if you could help me answering to a review I received:
I have a sample that was evaluated in two different moments for the same outcome (n=80, normal distribution, Mean 1=272±20, ...
0
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1answer
48 views
Does a paired t-test compare means?
The reason I ask is that I keep reading it compares means, yet everywhere people keep using box-plots for visualization, which seems fishy to me.
In more detail I would like to know whether ...
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1answer
39 views
Can I use a chi-square test to determine whether my samples are independent or paired?
I am conducting statistical tests for my current research project. Within the scope of this research project, I have two samples (divided by country clusters). The samples contain approximately 1500 ...
0
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1answer
22 views
Should I choose single model A+B+A:B or two models A at 2 levels of B?
I have a longitudinal model: response ~ device * time.
The device should lower the response over time.
There are two devices: A and B.
There is an interaction between the device and time.
The problem ...
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0answers
30 views
Too small sample size for Wilcoxon signed rank test, alternatives?
I have a statistical question about my research.
I performed photosynthesis measurements on leaves. I have 6 increasing light intensities, and for every light intensity, I measured the photosynthetic ...
2
votes
1answer
62 views
Using Paired-t test for n > 30 non-normal difference
I have data from a paired experiment (each participant does both the control and experiment and we find the difference). I know that for the paired t-test, an assumption is that the difference is ...
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0answers
18 views
What does, actually, the quantile regression asseses, assuming single two-level categorical covariate, difference in medians or median of differenes?
I know that, for a single, two-level categorical covariate, like sex={Male, Female}, the linear regression coefficients are about difference in means. It's like the t test. Does the quantile ...
3
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1answer
46 views
Is it appropriate to estimate the mean difference from a Wilcoxon p-value?
I am conducting a meta-analysis involving paired data (two instruments measuring the same thing). Original papers do not provide the standard deviation of the mean difference. One paper provides a p-...
2
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1answer
33 views
Is it possible to calculate the standard deviation of a mean difference using paired data?
Is it possible to calculate the standard deviation of a mean difference using paired data (ie. two instruments measuring the same thing). Eg. I have mean1 and SD1, as well as mean2 and SD2. I know the ...
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0answers
10 views
Pairing conditions to run lmer
I have six conditions and would like to create three pairs of conditions, so that when I run lmer it compares conditions 1 & 4, 2 & 3, and 5 & 6. Here's what I have at the moment:
...
0
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1answer
26 views
How to test similar distribution of categorical data (k=3) between 2 paired samples
I'm looking for a test to compare the distributions of categorical data (3 levels: J,N,P) between 2 dependent groups (paired samples: question_1, question_2).
We have 85 participants, each one of ...
3
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1answer
107 views
Why not include random slopes in a mixed model for a paired t-test
In class, we saw how one could use a mixed model as an alternative to the paired t-test. Lets say that we have subjects and each subject is measured twice. So we have a sample before (t = 0) and a ...
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0answers
22 views
Compare performance of libraries - test selection
I am trying to perform a comparison between three implementations of the same algorithm but using different libraries. However, I am not sure about my methodology. I am measuring elapsed time as a one ...
1
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1answer
26 views
Is it appropriate to use paired samples test for different days of the week?
Say we have a dataset of visitors to a mall:
...
1
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1answer
15 views
Paired or unpaired non-parametric 2 sample test?
I've got a relative simple question. I'm doing an imaging study with a phantom. I've run the same phantom through the MRI scanner 5 times, each time running the same scan twice and only varying one ...
