Dear Astina,

Please read the following article: "Sample size calculations: basic principles and common pitfalls" available at: https://academic.oup.com/ndt/article/25/5/1388/1842407/Sample-size-calculations-basic-principles-and

Thank you Dianatinasab for the reference.

I wonder whether we can use the given formula in the paper to do the sample size calculation for cross-over design or not?

given formula in the paper --> n= 2 ((a+b)^2) x Variance)/ ((mean group 1- mean group 2)^2)

Hello,

You can use G*Power software package program for calculating sample size. You can download the program freely from the link below:

http://www.gpower.hhu.de/en.html