(15 pts) A Randomized Clinical Trial was designed to compare the…
Question Answered step-by-step (15 pts) A Randomized Clinical Trial was designed to compare the… (15 pts) A Randomized Clinical Trial was designed to compare the effectiveness oftwo different antiretroviral (ARV) drugs in patients co-infected with TB and HIV inKorea. A sample size of 660 per group was chosen to have 90% power to detect adifference in mean CD4 at 1 year of 25 based on an estimated standard deviation of140. a. Which of the following is an accurate interpretation of the 90% power of thisstudy? (circle 1) 1. We will have a 90% chance of finding a significant difference if theobserved mean of the two treatment groups differs by 25 and the standarddeviation is 140. 2. There is a 90% chance that the observed difference will be 25 or more ifthe standard deviation is 140. 3. At the end of the study, if the standard deviation is 140 then on average90% of the data will be contained in a 90% confidence interval. 4. We will have a 90% chance of finding a significant difference if the truemean of the two groups differs by 25 and the standard deviation is 140. b. If the true standard deviation in this population is 210, will the study have moreor less power than expected? c. All participants will be observed for exactly one year, at which point their CD4count is measured. Once the study is over, what type of test can be used tocompare the observed differences in CD4 count between the two groups? d. The investigators are considering adding a third and fourth group who wouldreceive two other ARVs. If they do so, what test would you use to simultaneouslycompare the four ARVs with respect to CD4? e. What is the problem with comparing all pairs of ARVs using a t-test atalpha=0.05 for each? Math Statistics and Probability BIOSTATIST AS410 Share QuestionEmailCopy link Comments (0)
