Final answer:
The simplest subject in a quasi-experimental design refers to the experimental units or participants in the study. Therefore, the subjects or experimental units may be selected based on pre-existing characteristics, such as age, class, race, or education.
Step-by-step explanation:
In a quasi experimental design, the simplest subject refers to the experimental units or participants in the study. The experimental units are the individuals or groups that are being observed or tested in the experiment. For example, if the study is investigating the effect of a new teaching method on student performance, the students would be the experimental units.
Quasi-experimental designs are different from traditional experimental designs because they lack random assignment of participants to treatment groups. In a quasi-experiment, the researcher has limited control over assignment to treatment groups, often due to ethical or practical reasons. Therefore, the subjects or experimental units may be selected based on pre-existing characteristics, such as age, class, race, or education.