Question 4: (CLO 4, PLO 4) (25) An industrial engineer is investigating the effect of four assembly methods (W, X, Y, Z) on the assembly time for a LED. Four operators are selected for the study. Furthermore, the engineer knows that each assembly method produces such fatigue that the time required for the last assembly may be greater than the time required for the first, regardless of the method. That is, a trend develops in the required assembly time. The engineer suspects that the workplaces used by the four operators may represent an additional source of variation. A fourth factor, workplace (a, B, y,6) is added in analysis. Test the data of this experiment at a = 0.05, decide which factors are significant, and conclude appropriately. Order of Operator Assembly 2 3 Wa= 15 YB= 11 Zo= 10 Xy= 12 2 ZB= 12 Xa=9 Wy= 14 YS= 10 3 Yy= 8 W5=8 XB= 7 Za=8 4 X6=7 Zy=9 Ya= 18 WB= 11