(1) c. (2) a. (3) b. (4) d. (5) There are a lot of ways to test this. One example is to use a measurable work behavior (such as number of reports written in a week or number of clients served per day) as the operational definition of work productivity. The study could compare work productivity change (difference between work productivity before the study starts and work productivity during the study) for workers on different floors of the office (where one floor has the cappuccino machine and the other floor does not). Or work productivity could be measured for a week without the machine and then measured for a week with the machine and compared for the 2 weeks. Both designs involve a quasi-experiment. A true experiment would be difficult to conduct in the workplace. (6a) This is a causal hypothesis; thus, an experiment is the best design. (6b) A manipulated independent variable that includes random assignment of participants to a ginkgo biloba group and a control group that receives a placebo should be included. (7) External; Internal. (8a) archival data. (8b) systematic observation. (8c) survey/questionnaire. (8d) naturalistic observation. (9) negative. (10) Case study.