The use of weighted Z-tests in medical research.

  title={The use of weighted Z-tests in medical research.},
  author={K K Gordon Lan and Yuhwen Soo and Cynthia O. Siu and Mey Wang},
  journal={Journal of biopharmaceutical statistics},
  volume={15 4},
Traditionally the un-weighted Z-tests, which follow the one-patient-one-vote principle, are standard for comparisons of treatment effects. We discuss two types of weighted Z-tests in this manuscript to incorporate data collected in two (or more) stages or in two (or more) regions. We use the type A weighted Z-test to exemplify the variance spending approach in the first part of this manuscript. This approach has been applied to sample size re-estimation. In the second part of the manuscript, we… CONTINUE READING