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3
votes
3answers
107 views

What's a good way of graphically representing a very large number of paired datapoints?

In my field the usual way to plot paired data is as a series of thin sloping line segments, overlaying it with the median and CI of the median for the two groups: However, this sort of plot becomes ...
0
votes
0answers
6 views

compare data for self, ideal self and imagined self

I'm trying to compare data for an actual, ideal and imagined self, data was obtained by asking participants to fill out a BFI questionnaire three times, once for each self. The more I think about ...
0
votes
0answers
19 views

“CFINDER” output data importation and calculation of mean of pairs [migrated]

I face a problem: I have to import a text file (from_soft.txt, which is output from "CFINDER" software). It looks like this: ...
1
vote
1answer
40 views

How can I find out the needed sample size

I'm going to study if medical reconciliation diminishes the amount of inappropriate medications amongst elderly people in a small part of Sweden. I will count the number of inappropriate medications ...
2
votes
0answers
30 views

Comparing logistic regression models with paired data, population-averaged estimates and robust standard errors

I would like to ask if any of you have suggestions for comparing logistic regression models with paired data (3 observations/ID code), population-averaged estimates and robust standard errors (I am ...
1
vote
0answers
32 views

Overlapping or sliding interval matching

So I want to conduct a matched case-control study. One of the variables I want to match on is continuous variable, lets say age. I have converted this to categorical variable [17-19],[20-36],[37+]. ...
3
votes
1answer
196 views

Difference in Means vs. Mean Difference

When studying two independent samples means, we are told we are looking at the "difference of two means". This means we take the mean from population 1 ($\bar y_1$) and subtract from it the mean from ...
3
votes
1answer
26 views

What is a paired observation or paired variable?

The question kind of asks itself, can anyone explain what a paired observation or paired variable is in basic terms? My data consist of the number of words learnt in a week for 19 different ...
7
votes
2answers
229 views

Fisher exact test on paired data

Given $40$ cases with lung cancer and $40$ matched controls (without lung cancer) (matching based on age, sex, etc.). To try to find evidence between the effect of smoking on lung cancer, I used ...
0
votes
0answers
50 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 ...
0
votes
0answers
22 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: ...
0
votes
0answers
10 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 ...
3
votes
1answer
57 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
votes
2answers
167 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 $n$ ...
0
votes
0answers
25 views

Test for paired right censored data

I have a paired right censored data eg. ...
2
votes
0answers
26 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 ...
0
votes
0answers
27 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?
0
votes
0answers
50 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 ...
0
votes
0answers
39 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 ...
2
votes
1answer
106 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 ...
0
votes
0answers
25 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 ...
2
votes
0answers
80 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 ...
0
votes
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 ...
2
votes
0answers
61 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 ...
1
vote
1answer
46 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
votes
0answers
38 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
votes
2answers
102 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
vote
0answers
25 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 ...
1
vote
1answer
414 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 ...
2
votes
0answers
28 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 ...
1
vote
1answer
188 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 ...
0
votes
0answers
214 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 ...
4
votes
2answers
704 views

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

As in the title, I have two sets of data that are identical. I performed a paired t-test using R. The p-value for the difference estimated (which is essentially 0) is NaN. I wonder if there can be ...
0
votes
0answers
103 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 ...
1
vote
0answers
106 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.
1
vote
1answer
84 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 ...
1
vote
0answers
87 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
votes
1answer
44 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: ...
2
votes
0answers
201 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 ...
4
votes
0answers
60 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 ...
10
votes
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 ...
5
votes
1answer
98 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. ...
0
votes
2answers
361 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: ...
1
vote
1answer
64 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 ...
0
votes
0answers
60 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} ...
4
votes
2answers
83 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
votes
1answer
1k 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 ...
1
vote
0answers
43 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 ...
1
vote
0answers
136 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 ...
5
votes
2answers
687 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 ...