Standard deviation for the Fisher's z transformation of the correlation coefficient

[tqtbui]

Hello,

Thank you very much for the nice package. I have a question when using the package.

I was using the function esc_mean_sd() to convert means and sds to a point-biserial correlation coefficient. I wonder how the standard deviation for the Fisher's z transformation was calculated.

I learn that the formula is sqrt(1/(n-3)) from here, also from the book "Practical Meta-analysis", but when I double check the output of function esc_mean_sd(), it does not match.

Could you please help me explain why?

Thank you very much!
Best regards,
Trang Bui.