Final answer:
The term 'unit treatment effect (Y1-Y0)' refers to the difference in outcomes observed when subjects are exposed to a treatment versus when they are not, in a research study.
Step-by-step explanation:
The term "unit treatment effect (Y1-Y0)" in a research study represents a. The difference in treatment outcomes. In an experiment, this effect is observed by comparing the outcome of subjects when they are exposed to the treatment (Y1) against when they are not (Y0). If all subjects experienced both treatments, and the order of treatments was randomly assigned, this helps ensure that there are no differences between the treatment groups, effectively controlling for lurking variables. For example, if a study randomly assigns 100 college students to two groups with different tableware sizes to measure the amount of food eaten, with one group using normal-sized tableware and the other using tableware that is 20 percent smaller, the researchers are interested in measuring the unit treatment effect of tableware size on food consumption.