# Questions tagged [cohens-d]

Cohen's d is a generalized effect size measure. It is the difference between two group means scaled by the combined standard deviation. Cohen's d is used frequently in Jacob Cohen's text on power analysis, mostly to simplify the presentation of tables.

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### Converting Cohen's $d$ to Pearson's $r$ $\ne$ calculated Pearson's $r$

I was calculating effect sizes for an analysis and noticed by chance that Pearson's $r$ calculated from Cohen's $d$ with a conversion formula is not the same as when I calculate the correlation given ...
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### Meta analysis for a number of identical studies (with access to raw data)

I have access to about ten almost identical studies from ten different locations. They have been done different years, but with the same methodology. Each site was analysed and reported separately ...
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### Meta-analysis with rma() in metafor

I am working on a meta-analysis that has two moderator variables. Below is the code that I've figured out, but I'm not sure how to get the forest plot to show the overall model estimate. It's ...
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### One-sampled t-Test: large Cohen's d and large p value (is there a statisctical error?)

The p-value from a t-test I have run is unexpectedly large, considering Cohen's d. I calculated the one-sample t-test in RStudio for the following hypothesis: H2: For athletes who have already reached ...
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### Effect size and statistical significance correspondence

While I understand that it is possible to have a small effect size with statistical significance and a large effect size without statistical significance, is it ever possible to find this across two ...
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### Hypothesis testing Cohen's D -> actual difference in means (proportions)?

I'm trying to execute power analysis regarding proportions (successes of trials.) Using Python's stats models package I can specify a number of trials, an alpha and a beta and the MDE returned will be ...
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### Calculating global and local effects in a multiple regression using Cohen's d

I am calculating the effect size Cohen's d using linear regression. I am looking at the effect of disease on memory, and have also added age, education and sex as confounds to the regression. Cohen's ...
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### Transformation eta sqaured into cohens d or r

Is there a possibility to convert eta squared to Cohen's d or r? I uded this page (especially calculator 14) to transform different effect sizes into one: https://www.psychometrica.de/effektstaerke....
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### Cohen-d issues with pingouin ttest function for paired samples

I have two lists of time values, 'times0' and 'times1'. The data are paired (first value in times0 is paired with first value in times1, second value idem etc etc). I want the cohen-d of the t-test ...
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1 vote
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### common effect sizes in psychological research and calculation/ transformation

I am working on an empirical literature analysis. For that I have to code some variables in a specific manner (analysis includes 150 published studies in the field of behavior Neuroscience, ...
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### How do we call the distribution of a ratio consisting of a constant divided by a truncated normal random variable?

I have been thinking for a while about the following problem of Cohen's d effect size measure $d={\frac {\mu _{1}-\mu _{2}}{\sigma}}$ in random-effects meta-analyses for which I cannot find a more ...
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### Can I calculate Cohen's d (effect size) by hand if I have two means with their SD in a within subjects design?

I have several within-subjects studies that assess more or less the same intervention, but measure the outcome with different outcome measures. Most of my studies display the outcome in mean ± SD, ...
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### Equivalence test to compute no-differences between variables?

I need to state that there is no difference between the outcomes of the two tests (method 1 = fast and simple, method 2 = slow and hard to reproduce). I thought that a non-significant t-test would be ...
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### Converting unstandardised regression coefficients to Cohen's d for meta-analysis

I am conducting a meta-analysis of Cohen's d and some raw effect sizes are unstandardised regression coefficients. Of these unstandardised regression coefficients: Some are based on a binary ...
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### Two different versions of Cohen's D? Which one to use?

I am trying to measure the effect size of some variables between two different groups. I've taken some python code from a few tutorials, but they seem to be calculating it in different ways. I ...
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1 vote