Imph ★ 20230306 15:29 (527 d 20:51 ago) Posting: # 23487 Views: 2,488 

Hi, For sample size calculation in the case of full replicate design using R software, when specifying the 2x2x4 in the script, do we get the same sample size whether the design is to be : TRTRRTRT or TRRTRTTR. And same question for the partially replicated design TRTRTR vs TRRRTT. In the same way for manual computation, can we use the sample size formula presented by CHOW for the TRRTRTTR design to calculate the sample size for TRTRRTRT design. And same question, could the sample size formula of TRRRTT design be used for TRTRTR design. Thanks a lot. 
dshah ★★ India, 20230306 16:40 (527 d 19:40 ago) @ Imph Posting: # 23488 Views: 2,089 

HI Imph! The sample size would remain same because it is mainly driven by variability, desired power and ratio. Regards, Divyen 
Helmut ★★★ Vienna, Austria, 20230306 17:48 (527 d 18:32 ago) @ Imph Posting: # 23489 Views: 2,101 

Hi Imph, ❝ For sample size calculation in the case of full replicate design using R software, when specifying the 2x2x4 in the script, do we get the same sample size whether the design is to be : TRTRRTRT or TRRTRTTR. Yes. See there for the covered designs. ❝ And same question for the partially replicated design TRTRTR vs TRRRTT. These are 3period full replicate designs. See there for partial replicates. ❝ In the same way for manual computation, can we use the sample size formula presented by CHOW for the TRRTRTTR design to calculate the sample size for TRTRRTRT design. And same question, could the sample size formula of TRRRTT design be used for TRTRTR design. Why are you still referring to Chow’s approximations full of typos? At least when you deal with referencescaling you need simulations anyway. A formula does not – and cannot! – exist. — Diftor heh smusma 🖖🏼 Довге життя Україна! _{} Helmut Schütz The quality of responses received is directly proportional to the quality of the question asked. 🚮 Science Quotes 
Imph ★ 20230307 12:30 (526 d 23:50 ago) @ Helmut Posting: # 23490 Views: 2,074 

Hi, ❝ Why are you still referring to Chow’s approximations full of typos? At least when you deal with referencescaling you need simulations anyway. A formula does not – and cannot! – exist. I've been asked in my compagny to provide sample size formula for TRTR  RTRT and TRT  RTR designs. Thank you all. 