Sue wants to know whether wearing sunglasses improves driving performance. If she uses an independent groups design, she would m
anipulate the variable by randomly requiring half the drivers to drive with sunglasses and the other half to drive without sunglasses. having all drivers first drive without sunglasses and then with sunglasses. having half the drivers first drive without sunglasses and then with sunglasses and having the other half first drive with sunglasses and then without sunglasses. requiring all drivers to first drive with sunglasses and then without sunglasses.
randomly requiring half the drivers to drive with sunglasses and the other half to drive without sunglasses.
Step-by-step explanation:
When employing an independent group design in a research or experimental study, the different groups in the study are assigned entirely different subjects such that, subjects in the treatment group are different from those in the control group. Therfore, adopting an independent group design in the scenario described above means diving the subjects into two at random with one half driving with sunglasses and the other half having to drive without it.
The difference in fixed charge is $20; the difference in mileage charge is $0.50 per mile. So it will take $20/$0.50 = 40 miles for the extra mileage cost to eat up the savings in fixed cost. At that mileage, both companies will charge the same amount:
