RMP.7:5.1 - Two compatible tests among four reports

A seal engineer receives reports A, A2, B and C. A/A2 describe the same randomized accelerated test; A2 supplies its fuller outcome account. B describes an independent test of the same material contrast under compatible stress and measurement conditions. C describes in-service replacement choices under different conditions.

The synthesis question is the difference in mean time to the defined laboratory failure between the new and comparison seal under the specified accelerated conditions. Assume complete observed lifetimes, suitable approximately normal estimates, independent study estimates and a domain-justified common effect. The four-report map retains A2’s useful information without adding another independent estimate; C cannot estimate this laboratory contrast.

The recovered study estimates are 14 hours with standard error 4 for A/A2, and 8 hours with standard error 3 for B. Inverse-variance weights are 1/16 and 1/9. Their weighted estimate is 10.16 hours; its standard error is 2.4 hours, giving an approximate normal 95% interval of 5.46 to 14.86 hours.

The returned answer is a positive mean difference under the named laboratory conditions and assumptions. The study-specific estimates remain visible. The synthesis does not establish that the acceleration relation transfers to service or that a maintenance interval should change. C remains useful material for a different service-use question. An inadequate common-effect premise would reopen this calculation’s interpretation, even if the arithmetic were correct.