standard Normal distribution or the t -distribution on 2 degrees of freedom. In the absence of interference, a successful treated trial yields a response from F GLYPH<23> ( GLYPH<1> ) and an unsuccessful trial yields a response from F ( GLYPH<1> ) , so an unsuccessful treated trial looks like a control trial, but a successful treated trial looks like the maximum of GLYPH<23> independent control trials; see Lehmann (1953), Salzburg (1986) and Conover and Salzburg (1988) for discussion and history of this mixture model. Formally, in the absence of interference, the Salzburg model yields control responses from F ( GLYPH<1> ) and treated responses from (1 GLYPH<0> GLYPH<21> ) F ( GLYPH<1> )+ GLYPH<21>F GLYPH<23> ( GLYPH<1> ) , where Lehmann had considered GLYPH<23> = 2 , and Conover and Salzburg had determined the locally most powerful ranks as GLYPH<21> ! 0 , which are essentially WilcoxonGLYPH<146>s ranks for GLYPH<23> = 2 . In this mixture model, successful treated trials are from F GLYPH<23> ( GLYPH<1> ) and unsuccessful treated trials are from F ( GLYPH<1> ) , but trials are not labeled as successful or unsuccessful. We introduce interference into this model by assuming that a successful trial samples from F GLYPH<23> ( GLYPH<1> ) rather than F ( GLYPH<1> ) only if certain additional conditions hold deGLYPH<133>ned in terms of treatments assigned to the previous few trials. In Table 5, GLYPH<23> = 10 , but in Table 6, GLYPH<23> = 20 ; that is, a larger GLYPH<23> in Table 6 o⁄sets a smaller GLYPH<21> so that the power remains in an interesting range. The maximum of GLYPH<23> = 10 independent observations from a Normal distribution will often be smaller and more stable than the maximum of GLYPH<23> = 10 observations from a t -distribution with 2 degrees of freedom, and this may a⁄ect di⁄erent tests in di⁄erent ways. Four types of interference were simulated. With interference of type A, a successful treated trial that immediately follows a control trial has a response drawn from F GLYPH<23> ( GLYPH<1> ) , but all unsuccessful trials and all treated trials that immediately follow other treated trials have responses drawn from F ( GLYPH<1> ) . With interference of type B, a successful treated trial that immediately follows a treated trial has a response drawn from F GLYPH<23> ( GLYPH<1> ) , but all unsuccessful trials and all treated trials that immediately follow control trials have responses drawn 28