Sridhar.E ☆ India, 20210427 14:49 (54 d 18:00 ago) Posting: # 22331 Views: 671 

Hai all, can any one help how i convert inter subject CV to intra subject CV for sample size estimation. regards., Sridhar Edit: Category changed; see also this post #1. [Helmut] 
Helmut ★★★ Vienna, Austria, 20210427 15:14 (54 d 17:35 ago) @ Sridhar.E Posting: # 22332 Views: 560 

Hi Sridhar, » can any one help how i convert inter subject CV to intra subject CV for sample size estimation. What do you mean by ‘convert’? It’s like saying ‘convert an apple to an orange’. Both are approximately spherical fruits, more or less sweet and of similar weight. However, they are exclusively distinct. If you have a crossover study, both CVs are accessible. If you have a parallel design, you get only the total (aka pooled) CV (see this article). There is an infinite number of combinations of CV_{inter} and CV_{intra} which will give the same CV_{total}. $$\begin{matrix} s_\textrm{inter}^2=\log_{e}(CV_\textrm{inter}^2+1)\\ s_\textrm{intra}^2=\log_{e}(CV_\textrm{intra}^2+1)\\ CV_\textrm{total}=\sqrt{\exp\left(s_\textrm{inter}^2+s_\textrm{intra}^21\right)} \end{matrix}$$ — Diftor heh smusma 🖖 Helmut Schütz The quality of responses received is directly proportional to the quality of the question asked. 🚮 Science Quotes 