On an effect plot, when both lines have a slope, then there is (are) 1 point Two main effects and one interaction effect No main effect and no interaction effect One main effect and one interaction effect Two main effects and no interaction effect 6. Question 6 _______level designs are considered the most popular, useful, simple, and economical. 1 point Four Two Three One 7. Question 7 We want to use a fractional factorial design with the highest possible ________ for the amount of fractionation required. 1 point Factors Runs Resolution Trials