: e8 I# |( j' G1 J n$ Hwe fitted a random-effects piecewise logit model on the data set using the difference between A and B as an independent variable and accounting for potentially different slopes when the A-B difference was positive versus negative.4 B# C4 r- W9 t4 r/ q5 j
) e6 S2 i$ b* w
分析後,結果同時顯示了當A-B為正、A-B為負,之結果。0 ] `8 E7 p K
' J; @( B7 y5 t3 ]; S5 l2 S" l
我不懂的是作者如何處理A-B,A-B不是正值就是負值,或是0,當A-B是正值有資料的時候, ( O( I8 L( j6 q- X, C% j/ P# L$ z n負值就是missing value,vice versa, 因此在同一筆資料上,怎麼同時會有(A-B)為正值、為負值的資料?/ ]7 w' p( m; K0 E4 _: B