methods for comparison when the measurements to be compared are used each on the same subjects, so for each subject we get a pair of measurements.
Questions tagged [paired-comparisons]
179 questions
20
votes
5 answers
How to display error bars for cross-over (paired) experiments
The following scenario has become the Most-FAQ in the trio of investigator (I), reviewer/editor (R, not related to CRAN) and me (M) as plot creator. We can assume that (R) is the typical medical big boss reviewer, who only knows that each plot must…
Dieter Menne
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17
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2 answers
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 population 2 ($\bar y_2$). So, our "difference of…
user84756
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14
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3 answers
How can I predict the odds that a dodgeball team is going to win based on the winning history of its players?
Imagine there are 80 dodgeball players in the world. Each of them has played thousands of dodgeball games with the other 79 players in more-or-less random order. This is a world without teams (e.g., every player has a chance of being drafted in…
Behacad
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9
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3 answers
Paired t-test for binary data
I have one sample with n=170 and two binary variables (A,B) that can take as a value 1 or 0, where 1 counts as a success and 0 counts as a failure. What I want to know is whether the means of these two variables are equal.
To find this out I…
Martin
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9
votes
1 answer
Relative efficiency of Wilcoxon signed rank in small samples
I have seen in published literature (and posted on here) that the asymptotic relative efficiency of the Wilcoxon signed rank test is at least 0.864 when compared to the t test. I have also heard that this only applies to large samples, although some…
Jimj
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8
votes
1 answer
Why do zero differences not enter computation in the Wilcoxon signed ranked test?
The Wilcoxon signed ranked test tells us if the median difference between paired data can be zero. The test is executed by computing a statistic, then a z-score and comparing it to a critical value.
The thing that I find shocking is that we…
Martin Drozdik
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8
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1 answer
When does an unpaired test result in higher p-value than a paired test?
I determined some parameter in a group of subjects under two conditions, such that each subject was tested in both conditions. I want to know if the condition has an effect on the parameter. My design is obviously paired. However, previous…
Viktor
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7
votes
1 answer
How to calculate ratings/rankings from Paired comparison / Pairwise comparison of large data-sets?
As part of my graduate thesis (area: psychology) I have gathered preference data. The data includes approximately 50000 heads-up comparison between elementX and elementX. I have a total of 15 elements. The participant would be shown 36 comparisons…
ChrisFinland
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6
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1 answer
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.
in the following paper:
ALHASSEN, Fares, et al.…
Alessandro Jacopson
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6
votes
2 answers
Understanding formulation of hypotheses in difference between two sample means (z test)
Introduction
When testing a sample against a population, one has one of the following sets of hypotheses:
Two-tailed test: $H_0: \mu=\ldots$, i.e. "no difference", and $H_1: \mu\neq\ldots$
Right-tailed test: $H_0: \mu\leq\ldots$, and $H_1:…
Xiphias
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6
votes
3 answers
Computing Paired Samples (pre/post) Effect Size with Limited Information
I'm conducting a meta-analysis using the Hedge's g effect size statistic. Many of the studies are only reporting:
pre-treatment mean score
pre-treatment standard deviation
post-treatment mean score
post-treatment standard deviation
sample…
Chuck
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5
votes
1 answer
Optimizing matching of players in a tournament round
I am an organizer for a board game tournament. All of our players have an internal Trueskill rating we calculate to assist us with matching opponents for each round of the tournament. For each round, we can pair any player up with any other player…
TorgoGuy
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5
votes
2 answers
What's the official name of a 1 to 1 line plot?
I'm wondering if there is a name for one to one line graphs. Is it qq-plots? Is the qq-plots applicable on all types of variables or only quantiles? In other words, what's the name of the graph that compare two variables to assess if one variable is…
M. Beausoleil
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5
votes
1 answer
Difference or proportional
A report was claiming that older individuals were not appreciated at technology firms.
They studied a dozen factory locations of a tech firm where employees could (anonymously) suggest process improvements on a bulletin board in the hallway. Others…
CJ12
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5
votes
1 answer
Non-parametric version of paired t-test (Mann–Whitney U test)
I have data from 100 individuals doing a 2AFC under a control and a manipulated setting. I want to compare the means. I initially used a paired t-test. My supervisor noticed the distributions were not normal and recommended me using the Mann–Whitney…
LBogaardt
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