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3
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2answers
28 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
16 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
49 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 ...
1
vote
0answers
15 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
154 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
49 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 ...
3
votes
2answers
333 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 ...
0
votes
0answers
21 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 ...
0
votes
0answers
56 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
52 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
49 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 ...
0
votes
0answers
47 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 ...
0
votes
0answers
13 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 ...
1
vote
0answers
53 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
33 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: ...
0
votes
0answers
48 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 ...
2
votes
0answers
118 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
50 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
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 ...
5
votes
1answer
80 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
0answers
88 views

Paired test: many repetitions, few subjects

I have a situation similar to this: 9 normal-sighted subjects are each tested under two conditions: say, with and without spectacles (of a fixed power) and asked to reach towards an object many times ...
0
votes
2answers
162 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
50 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
55 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
votes
2answers
68 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 ...
0
votes
0answers
40 views

Average difference in averages and t-test

I'm currently working with some individual level data and have run up against a wall in figuring out the best way to analyse it. Let me describe: We have a sample of N=9000 Physicians. For each ...
2
votes
1answer
436 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
39 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
85 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
votes
2answers
366 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 ...
1
vote
2answers
79 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 ...
1
vote
0answers
135 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 ...
1
vote
0answers
372 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 ...
1
vote
2answers
85 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 ...
1
vote
1answer
156 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
votes
1answer
87 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 ...
2
votes
0answers
393 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 ...
0
votes
0answers
72 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 ...
0
votes
0answers
287 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
votes
0answers
129 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
vote
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 ...
0
votes
1answer
157 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? ...
5
votes
0answers
285 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 ...
2
votes
1answer
420 views

Confidence intervals and pairwise comparisons

Let us say I have the following pair wise test data: ...
3
votes
1answer
2k views

Output of one-tailed Wilcoxon sign rank test in R

I'm trying to assess the difference between two algorithms. They are stochastic, so I've run them multiple times against the same input files and noted their results. I want to determine whether my ...
2
votes
1answer
142 views

Permutation paired test with signed statistic

I have one paired data from 7 patients: $$(X_i ,Y_i)=\{(5,1),(-2,-4),(4,2),(-6,-3),(-3,-3),(-5,2),(3,1)\},\quad (i=1,\ldots, 7)$$ where $X$ means placebo $Y$ means the test drug. My classmate asked ...
2
votes
3answers
395 views

Once again: paired versus unpaired t-tests

This is much the same question that I asked a few weeks ago, but I hope to explain myself more clearly this time. I start with 40 mice. I use my own scheme, based on my own ideas for how to make the ...
0
votes
1answer
434 views

Is there a statistical significance in my paired sample data after performing Wilcoxon signed rank test?

I have a paired data consisting of $N$ = 421 samples. I would like to find out if there is statistical significance between the paired samples. Since, I do not know the underlying data distribution I ...
4
votes
1answer
1k views

Why is my bootstrap function for paired samples t test in R not returning the same result as SPSS?

I want to verify using a bootstrap approach the hypothesis about a lack of the intervention effect within a group of six patients: pre-(X) post(Y) intervention measurement. My data ...
8
votes
5answers
7k views

Paired versus unpaired t-test

Suppose I have 20 mice. I pair the mice in some way, so that I get 10 pairs. For the purpose of this question, it could be a random pairing, OR it could be a sensible pairing, like trying to pair mice ...