TEST QUALITY AND ESTIMATION OF THE EXPECT ED SAMPLE-SIZE IN SEQUENTIAL-ANALYSIS OF LINKAGE

It is shown that, when conducting sequential testing of linkage in ped igree samples, (1) type I and type II errors observed are less than ex pected and (2) the generally accepted method for determining the avera ge sample size, E(N), required for sequential analysis of linkage, und erestimates it. A less biased approximation of E(N) is proposed. A wid e scattering of actual sample sizes required for completion of sequent ial analysis is demonstrated, which puts practical use of E(N) into qu estion.