Because the A sample of Beltrán's urine test from the first stage tested positive for EPO, he can request that a B sample, which was drawn at the same time, be tested to confirm the result.
The source is of the electron cyclotron resonance (ECR) design and together with ion optics and beam transport lines is fitted to a UHV target chamber for first stage tests.
The result of the first stage test shows that the sample B should be assigned to class 9, but the sample A and sample C should be assigned to 1.2G, which is out of the expected classification, 1.4G and class 9, in the Model Regulations.
As first stage test we use the Hochberg test (Hochberg, 1988) such that the first stage p-value is given by The choice of the second stage test depends on the adaptation decisions in the interim analysis.
Using SDs as a first stage test offers no substantial advantages in test performance over the other IOTA strategies that we evaluated in this work.
The three-step strategies are: SDs as a first stage test, SRs for tumours in which the SDs are not applicable and SA for masses in which SRs are inconclusive; SDs as a first stage test, LR2 for tumours in which the SDs are not applicable and SA for masses in which LR2 yields a predicted risk of ⩾5% but <25%.
A strategy that used SRs as a first stage test and classified all inconclusive cases as malignant yielded a sensitivity of 95%95%5% CI 93 97%) and a specificity of 74% (95% CI 68 80% Table 4).
In a slight modification of Proschan and Hunsberger (1995), the conditional type 1 error rate 2013 of the final treatment-control comparison for and reduces to For notational convenience, the first stage test statistics is used.
As combination function we use the weighted inverse normal combination function approach of Lehmacher and Wassmer (1999) setting for, where is the weight of the first stage test statistics and the quantile of the standard normal distribution.
Assuming furthermore that the first stage sample sizes are balanced, that is setting (and therefore also that the final stage sample sizes are balanced between treatment arms), for formula 1994 simplifies to As in Section 4.1, for notational convenience, the first stage test statistics for comparing treatment i to the control are used.
