PPT Slide
Analysis of cluster RCTs.
492 patient RCT. Mortality was reduced from 36% (82/223) to 24% (67/269).
control 82 67.5 141 155.5 223
treated 67 81.5 202 187.5 269
?2 = Sum [(Observed - Expected)2/ (Expected)]
= (82-67.5)2/(67.5) + (141-155.5)2/(155.5) +
(67-81.5)2/(81.5)+ (202-187.5)2/(187.5)
With a ?2 of 8.129 on 1 df, p=0.004.