Conditions are altered and other variables are held constant?
Comparisons between two identical population, except one population is a treatment (exposed) group and the other is a control (unexposed)?
Researches don't know which group is treated untill after the data analysis?
Researches and subject do not know which is the treated or control group?
Response variable is affected by the independent variables (vertical Y-axis)?
Explanatory variables explain differences in the dependent variables?