An industrial engineer is studying the hand insertion of electronic components on printed circuit boards in order to improve the speed of the assembly operation. She has designed three assembly fixtures (F1, F2, and F3) and two workplace layouts (Ll and L2) that seem promising. Specialized operators are required to perform the assembly, and it was initially decided to randomly select four operators from the many qualified operators at the plant. However, because the workplaces are in different locations within the plant, it is difficult to use the same operators for each layout. Therefore, the four operators randomly chosen for layout 1 are different individuals from the four operators randomly chosen for layout 2. Each of the operators assembles 4 circuit boards for each of the three fixture types, with the 12 circuit boards assembled in random order. The 96 assembly times are measured in seconds. The engineer is interested in the effects of assembly fixtures (F), workplace layout (L), and operator (O) on the average time required to assemble the circuit boards.