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6 views

paired t-test for pairs each having more than one sample

I have a large and a small data set (the small data set is a subset of the large data set) with 2 columns(lets say var1 and var2). Now, based on var1 in the data set, I have sorted the large data set ...
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2answers
46 views

Comparing data that has been recorded on two devices

I have two data loggers which are recording a physiological signal. Device A is a system that has been in place for many years, and records data ~once/minute. Device B is a prototype device which ...
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16 views

Perceptual Agreement Statistics - Test for similarity between pairs?

I'm struggling to identify if there is a suitable and established test for determining if pairs formed from two separate populations are statistically similar when multiple people attempt to match ...
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0answers
31 views

ANOVA of pairwise (non-independent) data in R

I am trying to do a one-way ANOVA of data that is generated from pairwise comparisons, and am having difficulty resolving the problem of non-independence. I have 12 populations, and for each pairwise ...
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0answers
3 views

Does a within groups design necessarily mean the data is matched?

I am seeing conflicting information on this. The design is within groups with 4 groups. Each user experiences all four groups in a random order. There is no real reason the results of one group would ...
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0answers
39 views

Am I using Paired Statistical Test Correctly?

I am comparing a feature between correct & incorrect trials. There are N=1194 paired samples $\{x_i,y_i| i=1,2,...N\}$, where x is for correct trials and y is incorrect trials. I am using a ...
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1answer
26 views

Test if paired data are more similar than non-paired data

I have a set of ten samples, comprised of five pairs of twins, and I have calculated the pairwise distances between all ten samples. The question I would like to answer with this data is: Are ...
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0answers
32 views

Statistic for measuring amount of “reordering” between two vectors?

Ok, so here's the motivating situation: I have two pieces of software for which I can feed in an RNA sequence, and get out a numerical value. And while it's clear that one of the pieces of software ...
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2answers
54 views

Is paired t test sufficient to show the two data sets are similar

Let me give the details of my problem setting, we have a learning algorithm that can take a collection of algebra problems and automatically generate similar ones. Of course, an important question to ...
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0answers
19 views

Paired data with independent groups of treatment, how to plan and analyze?

I need your assistance, I am trying to design an experiment, and in order to do so I need to know how the data will be analyzed. The experiment in on rats. Each rat gets some treatment, and a measure ...
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1answer
128 views

ANOVA for paired data

I'm asking just of curiosity. If I have, for example, paired data and 3 groups (for example, baseline, 1 week, 2 weeks of treatment: I mean we take some samples at the baseline, then we apply some ...
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0answers
19 views

Test for pairs of small integers

I have two classifiers, say $A$ and $B$ and I am performing 10$\times$10-fold cross-validation on them and record the number of instances correctly classified from the test set. Unfortunately, the ...
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1answer
163 views

Bias-variance tradeoff in the paired t-test

Suppose we have $K$ subjects and a treatment with two levels, "Before" and "After". A paired t-test is equivalent to fitting a fixed effects ANOVA: $Y = Subject + Treatment +\epsilon$ It is also ...
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0answers
94 views

Should I use both paired t-test and intraclass correlation coefficient to examine the interrater reliability of an instrument?

As title, I am assessing the interrater reliability of a questionnaire (actually a Barthel Index (BI)) performed by four assessors (A,B,C,D) on about 25 test subjects. I plan to examine the IRR from ...
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2answers
442 views

What is the p-value for paired t-test if the two set of data are identical

As title, I have two set of data that are identical and performed paired t-test using R, the p-value for the difference estimated (which is essentially 0) is NaN. I wonder if there can be a ...
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0answers
31 views

Seeking covariates that can negate the effect size of treatment groups in an ANCOVA model

I was going to build an ANCOVA model with two treatment groups (climbed/unclimbed) and a set of 10 potential environmental covariates which may collectively remove the significance of the climbing ...
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0answers
85 views

Sample size calculation for paired t-test single arm using r

I am planning a study on alteration in AUC of a drug due to a surgery of gastrointestinal tract. It's a pre-post study. A group of patients will undergo blood sampling for AUC (area under curve) both ...
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0answers
86 views

Wilcoxon matched pair signed rank test after using CEM

Can I run a Wilcoxon matched pair signed rank test after using Coarsened Exact Matching to match data? If yes, please guide me through the process. I use STATA.
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1answer
58 views

How to test whether the absolute change of two paired samples different from zero

I have two paired samples. $\text{Group 1}: X_1,X_2, ...,X_n$ $\text{Group 2}: Y_1,\;Y_2,...,\;Y_n$. $(X_1, Y_1)$, $(X_2, Y_2), ..., (X_n, Y_n)$ are paired respectively. The null hypothesis ...
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0answers
57 views

How to analyze paired and longitudinal data

I want your advice regarding data I have, that comes from the Ophthalmic world. I have a small sample of 12 people (in future studies will be larger, this is a small pilot). Each person received a ...
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0answers
15 views

R Prefmod for paired comparisons

I'm trying to use the prefmod package to analyzed paired comparisons, but unfortunately the documentation is a bit poor and the author is no longer with us. I have a survey with 32 questions, split ...
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0answers
64 views

Comparison of multiple diagnostic tests with paired data

Good Day All, I am attempting to compare three diagnostic tests against a gold-standard and for simplicity sake, let us have all the outcomes be binary (disease/no disease). In this study study, all ...
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1answer
35 views

Are multiple paired t-tests among 2 groups safe and effective?

Part A: Suppose I have 2 groups (pre-treatment, post-treatment) and for each subject I record 3 variables. So my rows look like: ...
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50 views

May I treat two subject groups as if they were one when attempting to demonstrate the existence of an effect?

I have collected data from 88 human subjects. There is two subject groups, A (test) and B (control). Number of subjects in each group is 44. The subjects are paired between groups. There is two ...
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0answers
147 views

Can you combine z scores from similar but non-identical populations?

Suppose you have a group of people estimating the heights of trees. Suppose you have many different types of trees, some trees with a very low height, and others that are very tall. Suppose each ...
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53 views

Longitudinal paired analysis

I need your advice regarding a complicated design. I am testing data regarding new eye drops that suppose to decrease some quantitative measure. For every subject, one eye is randomly assigned with ...
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4answers
1k views

How can a t-test be statistically significant if the mean difference is almost 0?

I am trying to compare data from 2 populations to tell if the difference between the treatments is statistically significant. The data sets appear to be normally distributed with very little ...
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1answer
87 views

What is an “Unpaired Bland-Altman plot”?

I found this quote: Unpaired Bland-Altman plots were used to check systematic or bias errors in the SPECT myocardial uptake coefficients with respect to the reference standard PET data. ...
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2answers
222 views

Alternative to multiple Fisher's Exact tests

I have count data for a pair of test and control populations of samples for a variable that takes a value of either A or B for a sample: ...
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1answer
55 views

When Should The Following Tests Be Run

What are the assumptions behind each of the following types of tests (i.e. what are the prerequisites to running each test). Paired-t Sign Two-Sample t Pooled Two-Sample t Two Proportions F I ...
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0answers
58 views

Writing R Function To Determine Which Statistical Test Should Be Run

I am trying to write a function in R that determines which of the following statistical tests should be run on a set of data: {paired-t, sign, two-sample t, pooled two-sample t, two proportions, F} ...
3
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2answers
75 views

Can non-paired data have dependency?

I have two vectors of data of different sample size. Both are the same experiment, but executed in a different environment. Since the sample sizes are different and they don't share any subject, is it ...
2
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1answer
661 views

Missing data SPSS paired samples t-test

I have approximately 20% data missing in my sample (n=3215). I aim to assess the pre-post differences on a psychometric scale. Especially post measures are missing because of follow-up issues. What to ...
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0answers
40 views

How to compute the probability that there is no difference between matched pairs

I am looking for a way to find the probability that there is no difference between a matched pair of binary data. I don't want to know whether the difference is statistically significant, I want to ...
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93 views

Reducing sample size to change from a paired to unpaired design

I have two groups of data, one consisting of 9 subjects and another consisting of 5 subjects. In the 9 subjects group, 5 of those could be paired with the 5 subjects from the other group. I could run ...
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2answers
460 views

Critical effect sizes and power for paired t test

Is there some sort of easy way to calculate the required sample size for a paired t-test with an effect size of 2 standard deviations? In my line of work, we often use an effect size of 2SD from the ...
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2answers
80 views

Difference AM-PM or PM-AM for a paired T-Test - to test if the mean of the differences = 0?

I have a paired set of data, that I wish to perform a t test on to test if the mean of the differences is equal to 0. I notice there is a difference between if I do AM-PM vs PM-AM - which way should ...
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0answers
140 views

Is it correct to use a paired t-test for this question?

this is an exam practice question for my 1st year stats class and I just want to see if I have approached this problem correctly and to clarify my understanding. Here is the complete question: A ...
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0answers
459 views

mixed effect model for method comparison of time series of paired measurements

A coworker and I are trying to analyze agreement between two measurement methods. I apologize in advance for needing some extra explanation due to the fact I'm an engineer whose statistics background ...
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2answers
95 views

Prey preference - can I use a paired t- or wilcoxon test?

I have done an experiment in which I looked at the prey preference of an aquatic invertebrate. I used 10 containers all with one predator but with different densities of prey. I used two different ...
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1answer
160 views

Paired t-test or Independent t-test

I am new to this forum so here goes. I have an assignment question I need help with. A scientist has performed some experiments to determine the relationship between the concentration of phosphorus ...
4
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1answer
91 views

t-test or not, independent or not

I have searched, but I'm unable to understand: please help a beginner. 1) Scenario - 10 people (random sample) are asked 6 questions. The 6 questions are divided into 2 categories (i.e. 3 long words ...
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0answers
458 views

Methods for comparing proportions in partially overlapping samples

We conducted 2 similar surveys in parallel to a group of health care facilities. One was sent to managers, one to staff. Some questions were identical, others asked about different areas of the ...
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0answers
74 views

method and needed tests for assumption in analyzing a paired sample Likert measure?

I am writing an exploratory paper considering an argument that a certain reaction that can arise in the viewing of art can serve as an empirical indicator that another particular cognitive process has ...
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0answers
311 views

Which test to check statistical relationship betwen paired/unpaired data?

I have data that is in-between of "independent samples" and "paired samples". About 50% to 70% of observations are matched (paired) and the rest miss a pair. Which test should I use - chi-square ...
2
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0answers
139 views

Random Forest or other machine learning techniques with paired samples

I am trying to select features from paired samples and was wondering if there are methods out there that adapt random Forest or other machine learning algorithms to paired samples i.e. if randomForest ...
1
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1answer
100 views

Can high quality clusters be found in every data set?

In my data I have 3 clusters with average silhouette 0.61 and very few negative values. I repeated k-means 10 times with k ranging from 2 to 10. This seemed to work ok, but the problem is that I got ...
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1answer
162 views

What paired test should I use and how do I interpret it?

The question: The data file contains observations of the wavelengths (in nanometers) of the main color in two kinds of shoe polish. (Sample size = 100). Are the wavelengths significantly different? ...
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318 views

Compare two survival curves for paired data

I want to compare two different methods for detecting status change in a survival analysis. A group of subjects is being followed for a longer period (many years), and two examination methods have ...
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1answer
452 views

Confidence intervals and pairwise comparisons

Let us say I have the following pair wise test data: ...