Rogers, Farlow, and colleagues (1998) conducted an experiment to investigate
whether donepezil improved cognitive function in patients with mild to moderate Alzheimer's disease (AD). A total of 1,775 patients were randomly assigned to treatment with either donepezil or a placebo (a look-alike pill with no pharmacological effect). Cognitive function, as measured by the Alzheimer's Disease Assessment Scale (ADAS-cog), was significantly improved in patients taking donepezil compared with the placebo group at weeks 12, 18, and 24. [Source: Rogers, S. L., Farlow, M. R., Doody, R. S., et al. (1998). A 24-week, double-blind, placebo controlled trial of donepezil in patients with Alzheimer's disease. Neurology, 50, 136-145.]
In this experiment, the independent variable is ____ , and the dependent variable is ______ .
The individuals who are in the control condition are typically referred to as the control group. Here, the control group consists of _______ .
___________ is a construct that is being tested in this experiment, and the experimenters have operationally defined it as __________.