libaiyi Junior China, 20180727 05:34 (edited by libaiyi on 20180727 07:47) Posting: # 19107 Views: 2,731 

Hi, I have a naive question about the results of sample size based on SampleN.TOST, sampleN.NTIDFDA, sampleN.HVNTID etc. For example, sampleN.RSABE(CV=0.3) I want to know if the target power is 0.8, the sample size is 45 for each group or for whole study. The other question, when we apply power.TOST, the sample size we need to fill in should be number in each group or whole study. Third question, I am confused about the relationship between power and period. Are the power calculation method applied in 2*2, 3*3 and 2*4 designs the same? For example, if I have the result like this of the study design as TSR, could I use the same method to calculate power separately for TR and SR? Should I get two power as the result? And, what about parallel design? Thanks in advance! 
Helmut Hero Vienna, Austria, 20180727 11:24 @ libaiyi Posting: # 19108 Views: 2,607 

Hi libaiyi, answering parts (traveling)… » I have a naive question about the results of sample size based on sampleN.TOST, sampleN.NTIDFDA, sampleN.HVNTID etc. » For example, » sampleN.RSABE(CV=0.3) » … » n power » … » 45 0.80344 » » I want to know if the target power is 0.8, the sample size is 45 for each group or for whole study. Type help(sampleN.TOST) , etc.It is always the (total) number of subjects in the study. » when we apply power.TOST, the sample size we need to fill in should be number in each group or whole study. As above. — Cheers, Helmut Schütz The quality of responses received is directly proportional to the quality of the question asked. ☼ Science Quotes 
libaiyi Junior China, 20180727 11:49 @ Helmut Posting: # 19110 Views: 2,603 

Hi, Helmut Thanks for answer my question while you are traveling. Enjoy yourself! 
ElMaestro Hero Denmark, 20180727 19:57 (edited by Ohlbe on 20180728 11:07) @ libaiyi Posting: # 19111 Views: 2,572 

» Hi Libaiyi, » » » I am confused about the relationship between power and period. Are the power calculation method applied in 2*2, 3*3 and 2*4 designs the same? For example, if I have the result like this of the study design as TSR, could I use the same method to calculate power separately for TR and SR? Should I get two power as the result? And, what about parallel design? » » » » That table looks strange. You seem to have a pair for which the CI is not estimable?? And what about alpha 0.1? Would you be after a twosided CI with 80% coverage (yes I am aware of the ridiculous alpha in the usual SAS code for BE, but is this table derived from one such)? I have no idea what the intention is, it just looks strange to me, and I am sure that if I got such a table in one of my studies then I would not be answering the question I was really asking. Edit: screwed up post deleted [Ohlbe] — if (3) 4 Best regards, ElMaestro "(...) targeted cancer therapies will benefit fewer than 2 percent of the cancer patients they’re aimed at. That reality is often lost on consumers, who are being fed a steady diet of winning anecdotes about miracle cures." New York Times (ed.), June 9, 2018. 
d_labes Hero Berlin, Germany, 20180728 12:43 @ ElMaestro Posting: # 19113 Views: 2,519 

Dear ElMaestro, dear Libaiyi, » That table looks strange... For me too. Seems Libaiyi has used a design, in which one of the contrasts is not estimable, for what reasons ever. Libaiyi, could you give is some more info about the design and the SAS code used? » And what about alpha 0.1? That's a peculiarity of the almighty SAS which always calculates a two sided CI, i.e. if you specify alpha=0.05 (the default) it calculates the 95% CI (0.025 to each side) and not the appropriate 90% CI. — Regards, Detlew 
libaiyi Junior China, 20180731 04:13 @ ElMaestro Posting: # 19118 Views: 2,462 

Hi, ElMaestro Sorry for the SAS result last time, here is the modified result. The design here is a threeperiod sixsequence William design. I just wondering when the study design is replicated, dose the power calculation method the same as what used in simple 2 by 2 cross over design? Thank you so much! 
ElMaestro Hero Denmark, 20180731 11:07 @ libaiyi Posting: # 19119 Views: 2,443 

Hi libaiyi, » The design here is a threeperiod sixsequence William design. I just wondering when the study design is replicated, dose the power calculation method the same as what used in simple 2 by 2 cross over design? Thank you so much! I am still somewhat baffled. You have different SE's for the three comparisons, possibly suggesting that you are employing an EMAstyle BE evaluation? Anyways, if you are going for a 222BE design, then you can look at your MSE from the ANOVAs (plural, right?), convert them to CVs via CV=sqrt(exp(MSE)1) and you have a decent variability estimate to plug in for any crossover design with or without scaling. Your best point estimate is exp(.2088)~0.81 with upper limit ~0.88, for the TS pair. The others appear worse. I'd personally think twice, but I am widely known as a backward cowardly chicken. Note, the opinion above implies logarithms and standard BE thinking. Edit: Congratulations to your post № 1,500! [Helmut] — if (3) 4 Best regards, ElMaestro "(...) targeted cancer therapies will benefit fewer than 2 percent of the cancer patients they’re aimed at. That reality is often lost on consumers, who are being fed a steady diet of winning anecdotes about miracle cures." New York Times (ed.), June 9, 2018. 