CONSTITUTION:Keyboard 1, display equipment 2, printer 3, oscillator 4 and memory 6 are connected to operation part 5 of a cash register, and the oscillated output of oscillator 4 is supplied to operation part 5, and clocks of memory 6 are counted up at a fixed period. Memory 6 is ...
coefficient estimates for the interactions between eachTreatvariable and year dummies for periods four or more years prior to treatment. Analogously, the t > = 4 value is the average of the estimates for the interactions betweenTreatand year dummies for periods four or more years after treatm...