Experiment Design Analysis - Gas Mileage

Marcia heard that premium unleaded gasoline gives her better gas mileage than regular unleaded. In her experiment, she filled up with tank # 1 right before she drove to Seattle. With tanks 2, 3 and 4 Marcia drove to school and work in Oak Harbor.

  1. Question/Problem:
     
     
     
  2. Hypothesis with a prediction:
     
     
     
  3. Manipulated variable:
     
     
  4. Levels of treatments:
     
     
  5. Responding variable:
     
     
  6. Controlled variable:
     
     
  7. How would you improve this experiment?
     
     
     
     
  8. Why did Marcia uses two tanks for each gasoline type?