![]() Approximate tests based on these designs are proposed for use when the number and timing of analyses are random. of lower expected sample size normally achieved by a group sequential test are reduced when there is a delay in response. Tables of critical values for both one-sided and two-sided symmetric designs are provided, thus allowing easy determination of sample sizes and stopping boundaries for a group sequential test. These symmetric two-sided group sequential tests are found to have improved overall efficiency when compared to the tests proposed by Pocock (1977, Biometrika 64, 191-199) and O'Brien and Fleming (1979, Biometrics 35, 549-556). The symmetric tests are then extended to a two-sided hypothesis test. maximized sequential probability ratio test (MaxSPRT PDF 22. The standard group sequential test is statistically valid under the assumption that the patient population remains unchanged from one interim analysis to another. We present a one-parameter family of symmetric one-sided group sequential designs that are nearly fully efficient in terms of the average sample number. than among the comparison group, the vaccine may be associated with an adverse event. In clinical trials, a standard group sequential test with a fixed number of planned interim analyses is usually considered to assess the effect of a test treatment under study. being overlooked and excluded by a person or group (Wesselmann et al., 2016). Group sequential test designs that do not treat the hypotheses symmetrically may not fully address this concern since early termination of the study may be easier under one of the hypotheses. The present study tested the influence of social exclusion on smartphone. optimized group sequential study designs to the analysis of genetic linkage (one-sided mean test) and association. ![]() In Phase III clinical trials, ethical considerations often demand interim analyses in order that the better treatment be made available to all patients as soon as possible.
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