The regression models considered are shown to arise from radioactive tracer experiments using compartmental models. For such models the regression equations are shown to be linear combinations of the ...

Simultaneous equations are two linear equations that can be solved using bar models. By remembering that the same letter will always have the same value we can work out the missing values.

Goenner (Conflict Management and Peace Science, 28 (5): 1–20, 2011) criticizes the simultaneous equations regression model (SEM) of bilateral trade flows (BT) and militarized interstate disputes (MID) ...