Questions tagged [fisher-transform]
Fisher's z-transform is a transformation that is applied to the correlation coefficient, r, for use in hypothesis testing & constructing confidence intervals.
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Normality of $z$ transformation without preliminary assumption
Assuming data $X_1,...,X_n, Y_1,...,Y_n$ we have Pearson correlation $r=\frac{Cov(X,Y)}{\sigma_X\sigma_Y}$. Fisher's $z$ transform is then $$z=0.5\log\left(\frac{1+r}{1-r}\right)=\tanh^{-1}(r)$$
If $(...
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Fisher r-to-z transformation: comparing correlation coefficient of multiple samples
I am comparing the linearity of a regression model for two independent devices (n=10 each device group). The data is force (newtons) over time (seconds). The regression models show R^2 values of 0.9 ...
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Is Fisher transformation appropriate for magnitude squared coherence and phase locking value?
Fisher transformation, or hyperbolic arctangent, is recommend before performing arithmetic on correlation coefficients (e.g., estimating confidence intervals), because it makes their distribution ...
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Standard Error of Truncated Fisher's z Transform
I have a question regarding data following the truncated Fisher's z-transform. I currently understand that the correlation coefficient data, after the unbounded Fisher's z-transform, has a standard ...
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Polychoric Correlations to Fisher's Z Transformation
I'm interested in conducting a meta-analysis of polychoric correlation coefficients using metafor package in R.
When performing a meta-analysis with Pearson ...
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Seeking Feedback on Mixed-Effects Model with Weighted Observations
I've been working on a project where I'm comparing different methods using a mixed-effects model, and I'd appreciate some feedback on my approach.
Background:
I have a dataset with several variables:
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Can I compare Pearson's r and Spearman's rho with Fisher's r to z transformation?
I'm using the tool in the following website to compare correlation coefficients:
http://vassarstats.net/rdiff.html
The tool uses Fisher's r to z transformation to ultimately compare two correlation ...
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Fisher Z transformation still not normal
I have 18 different groups that I need to compare. I used the raw values from a neuroimaging file to represent synchronization between two brain regions (which ranged from 0 to 1) and Fisher Z ...
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I want to conduct some test on a large correlation matrix in r
The data I have is essentially the number of times two students were seen together.
So student 1 and 3 were seen the most amount of times together, then 2 and 3, then 1 and 2.
The correlation matrix ...
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Negative data for log transformation [duplicate]
I am analysing data on hourly electricity prices to try to do some forecasting, in my dataset I have mostly positive values, but some negative, around 20 per region for the two year duration. I want ...
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How to correctly compare 2 correlation values using the Fisher r-to-z transform?
In https://www.statisticshowto.com/fisher-z/, it is stated that “But it’s probably most commonly be used to test the significance of the difference between two correlation coefficients, r1 and r2 from ...
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Interpreting fisher’s Z transformation and correlations
Part of my planned analysis in a paper is testing the difference in strength of correlations between depression and other things like social relationships and quality of life. This test is set up with ...
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Z-transforming Pearson correlation vs. converting to mutual information: they seem to be related, but how?
EDIT: By noodling around a bit, I found that they can actually both be re-arranged into even more similar forms:
$Z = -\frac{1}{2}(\ln(1-\rho) - \ln(1+\rho))$
$I =-\frac{1}{2}(\ln(1-\rho) + \ln(1+\rho)...
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A question about fisher's z transformation detail of his paper published in 1921
Typically, people will use Fisher's z-transformation (arctan) to turn the r into a variable that is approximately normally distributed. When I look though his paper published in 1915(https://www.jstor....
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How to meta-analyze latent correlations when r=1?
I compiled 11 correlations from k=11 studies. Let's just call the two variables $A$ and $B$. The correlations were very high and ranged in between $r=.54-.84$, but there is one study that reported a ...
