11/21/2022 0 Comments Sequential testing procedure![]() They developed and evaluated a new method to determine the optimum cutoff score of the screening test, a method based on minimization of the loss represented by the (weighted) numbers of false positives and negatives in the screening test. They investigated efficiency and validity as a function of the cutoff score of the screening test. In a simulation experiment based on the data from those tests, the authors considered the first day as the screening test and the second day as the second test. In 1994–95, first- through fourth-year (Group 1) and sixth-year (Group 2) medical students at the University of Maastricht took SP-based tests. This study investigated whether sequential testing increases efficiency with only a minor decrease of validity. In this approach, students take a short screening test only those who fail take a second test. The Annals of Mathematical Statistics, 16(2), 117-186.Educators who use standardized-patient-based (SP-based) tests may save resources by using sequential testing. Sequential tests of statistical hypotheses. (1985) Sequential Analysis: Tests and Confidence Intervals. This formulation does not incorporate economic costs. There is plenty of theory there if you want, including certainty of stopping, expected sample sizes, and efficiency. $A_m$ is called the acceptance number and $R_m$ is called the rejection number. Then you accept $H_0$ if $d_m \le A_m$, accept $H_1$ if $d_m \ge R_m$, and continue sampling if $A_m < d_m < R_m$. Let $d_m$ be the number of bad outcomes at the $m$th trial. Then, you monitor the number of bad outcomes. To apply the procedure, you will need to specify a probability that is good enough to accept ( $p_0$), and a probability that is bad enough to reject ($p_1$), in addition to your usual error rates $\alpha$ and $\beta$. However, for sequential testing, the original paper on the sequential probability ratio test by (Wald, 1945) is very readable and available online. There is plenty of literature on acceptance sampling and process monitoring that also bears on this problem if you need to perform batch sampling. (For example, see II.3 of (Siegmund, 1985)). Your case is usually covered as an example along with the normal distribution. There are many references to cover the theory of sequential testing. If you have very little cost to analysis, then you can just do sequential testing. That is most useful when it is costly to perform interim analyses. It might be that the group sequential testing approach is overkill for your application. SEQUENTIAL TESTING PROCEDURE HOW TOThus I failed to find a guidance how to design the sequential experiment protocol for my set-up: given pre-fixed values for Type I and II errors, the number of stops, I want to find p-value thresholds (or other stopping criteria) for each of the stops.Ĭould anyone provide me with a relevant link? However, as the topic is mostly studied in the medical context, usually a control/test split is assumed. There exist quite extensive literature on sequential testing, R package gsDesign, etc. This idea is inspired by O'Brien
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