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26 views

Comparing paired data in two different treatment groups

Suppose I have two groups of participants. The first groups gets treatment 1 and the second group gets treatment 2. The first treatment is a standard treatment and the second treatment is something ...
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0answers
20 views

Repeated Observations Due to Pairings in Logistic Regression

I have data with repeated observations within a given year. Here's a snippet of the data: ...
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0answers
4 views

Analysing matched pre post surveys that have definite answers

I have pre - post matched survey data that contains True/False responses and Multiple Choice responses. These questions have definitive answers, it is not a Likert scale. How can I compare the ...
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1answer
32 views

Is the significance of difference in slopes equivalent to the significance of the slope of the difference of two series?

Say you have an independent variable, $x$, and two dependent variables $y_1$ and $y_2$. I want to calculate whether these two variables have a significantly different slope. I can do it by calculating ...
3
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2answers
87 views

Mann-Whitney U test and paired data

I've read that working with paired data requires other method than Mann-Whitney $U$ test. I am not sure about how formally accurate is this statement. Reasons: Suppose that there is a set of $n$ ...
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0answers
20 views

Test for paired right censored data

I have a paired right censored data eg. ...
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0answers
21 views

Estimating distribution from pairwise comparisons (crowdsourced)

I would like to estimate a discrete probability distribution, for instance, occurrences of animal species in a geographical area (e.g. from all the animals 20% are bears, 10% are wolfs, 5% are ...
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0answers
22 views

Other statistical tests for paired data

Are there other statistical tests available to compare paired sets of data e.g. {1, 2, 2, 3, 4} v's {3, 3, 3, 2, 5} for similarity, aside from the paired Wilcoxon and paired Student t-test?
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31 views

How to determine correct statistical test for repeated measures, differing treatments in same subject experiment

Our hypothesis is that treatment 1 changes our outcome measure by some amount, and that treatment 1 combined with treatment 2 changes our outcome measure by a larger amount. For each subject, the ...
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32 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
66 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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0answers
19 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
53 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
5 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
53 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
31 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 ...
3
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0answers
33 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 ...
3
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2answers
70 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 ...
1
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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
230 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
25 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
178 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
143 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
564 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
35 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
95 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
101 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
69 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
61 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
21 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
73 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 ...
0
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1answer
39 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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0answers
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
175 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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54 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
2k 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
92 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
301 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
63 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} ...
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2answers
78 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
917 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
41 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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0answers
106 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 ...
3
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2answers
554 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
82 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
154 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 ...
2
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0answers
522 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
100 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
165 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 ...