How does Jasp calculate d effect size for paired-sample t-test

Eris

Hi all,

I need to report the formula of how Jasp calculates d effect size for paired sample t-test. Is it possible somehow to get access to the piece of code? I read an old thread about it but the replies were inconsistent.

Many thanks,

Eris

JohnnyB

Hi Eris,

In the R-code on line 243, there is the calculation of cohen's d:

d<- mean(c1-c2) / sd(c1-c2)

So the mean of the difference scores of the two groups, divided by the standard deviation of the difference scores. It would indeed be good to include this in our help files, because it does not explicitly state this calculation there.

Kind regards,

Johnny

Eris

Many Thanks Johnny;

A reviewer asked for the exact formula.

Cheers,

Eris