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3
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1
answer
1k
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Reporting Fisher-transformed Pearson's correlations when the magnitude of difference is rele...
As soon as such correlations become high, Fisher-transforming the correlations will (visually) pronounce differences between the pairs better than leaving the correlations uncorrected. … I can understand the motivation behind including the matrices in this way in a paper, but is it really correct to report Fisher-transformed correlation matrices in this case? …
5
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3
answers
5k
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Fisher R-to-Z transform for group correlation stats
I have independent correlation coefficient measures for each subject. I would like to test whether the correlation coefficient of the group is significantly different from 0. … My understanding is that the Fisher's transform is used because the r's are not normally distributed. …
26
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2
answers
31k
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How to calculate a confidence interval for Spearman's rank correlation?
Wikipedia has a Fisher transform of the Spearman rank correlation to an approximate z-score. Perhaps that z-score is the difference from null hypothesis (rank correlation 0)? … use the Fisher transform to get the 95% confidence interval? …
0
votes
0
answers
16
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Meaning of "Fisher transformation of cross-correlations"
I am not sure I understand the jump from cross-correlation to Fisher's Z-transform: isn't Fisher's transform based on the Pearson correlation coefficient? … What does it mean to apply Fisher's Z-transform to a cross-correlation? …
2
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0
answers
709
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Simple mean or weighted mean of Fisher z-transformed correlation coefficients
I follow the standard prescription:
apply the Fisher z-transformation to my $\rho_i$ ($z_i$ are the z-transformed correlations)
perform the mean $\bar{z}$ of the $z_i$
and then apply the inverse transformation … I went through the literature of the Fisher transform but I cannot find any clue on this specific point. …
0
votes
0
answers
552
views
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 … Or I do r1-r2 and apply the transform on this output? …
0
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1
answer
453
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Confidence interval of correlation coefficient with different null hypothesis
$\rho$ between these sets and a 95% confidence interval with a Fisher transform, as follows:
r, p = st.pearsonr(x,y)
r_z = np.arctanh(r)
se = 1/np.sqrt(x.size-3)
alpha = 0.05
z = st.norm.ppf(1-alpha … Given that I know the Fisher transform is an asymptotic approximation for large $n$, is there a better method than above for calculating the confidence interval I want? …
7
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2
answers
10k
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Exact central confidence interval for a correlation
In the introduction, there is a table of before/after treatment values called cd4, and the correlation $\hat\theta$ is given as 0.723. … When I key in the data and compute a confidence interval by hand in R, either using the Fisher transform or the T distribution, I don't get that interval. …
8
votes
1
answer
3k
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Why is fisher transformation necessary?
I read that the correlation coefficients have to be converted by using a fisher-transformation when one wants to test their significance (like here When is Fisher's z-transform appropriate? ). … https://blogs.sas.com/content/iml/2017/09/20/fishers-transformation-correlation.html
Ok, so what? What does it mean that it is bounded? When there are no bounds, then "bounds" would be +/- oo. …
0
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0
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65
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Fisher transformation
I am currently working with panel data, namely its correlations. The data is three-dimensional. I am looking for a way to aggregate the correlation coefficients. … I found a model which uses the Fisher transformation to do this as shown as follows:
Let $i$ be an invidual (20), consisting of 5 buckets $b$, each containing its own time-series, $j$, $n_j = 3000$ For …
1
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0
answers
101
views
Non-normal residuals when the outcome variable is a Fisher $Z$-transformed correlation coeff...
I’m running a multilevel model in which the outcome variable is a Fisher Z-transformed correlation coefficient. … Edit: As per @nick-cox's comment, I've pasted a few histograms below indicating the distribution of the original correlations and of the Fisher-transformed correlations. …
2
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1
answer
2k
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Fisher z-transformation and normality
I have 100 50x50 correlation matrices, which I have all Fisher z-transformed. I understood that this results in the all the entries of one matrix being approximately normally distributed. … Does the Fisher z-transformation implies that? …
1
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1
answer
245
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What is the procedure for a mixed effects analysis of covariance?
I have implemented a mixed model to assess relationships between the observations using Fisher-transformed correlation coefficients. … I then perform a Fisher-transform on the 9 resulting correlation coefficients to get 9 z-scores. Then it's a simple matter of testing whether or not those z-scores differ from 0. …
14
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1
answer
12k
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Significance test on the difference of Spearman's correlation coefficient
Let $z_A$ = the Fisher transform of the observed correlation of set $A$,
$z_B$ = the Fisher transform of the observed correlation of set $B$. … For $i = 1,\dots,n$, let $y_{A_i} = nz_A- (n - 1)z_{A'i}$, where $z_{A'i}$ is the Fisher
transform of set $A$ of the one-left-out correlation obtained by deleting
$(x_i,y_i)$, re-ranking, and re-computing …
10
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1
answer
22k
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Fisher's z-transform in Python?
I want to test a sample correlation $r$ for significance ($n=16$), using p-values, in Python. As I have understood from this question, I can achieve that by using Fisher's z-transform. … Is there a Python module, which allows easy use of Fisher's z-transform?
I have not been able to find the functionality in SciPy or Statsmodels. …