A chemical engineer is designing the production process for a new drug. The drug will be manufactured in batches, and the yield will be higher or lower depending on the temperature and pressure used. The engineer decides to run an experiment using three temperatures and two pressures to search for the combination that leads to the highest yield of the drug in each batch. She processes four batches at each temperature-pressure combination and measures the yield of the drug in each batch.

1. What are the experimental units?
2. What is the response variable?
3. How many factors are used?
4. How many treatments are used?
5. How many experimental units are required for the experiment?