Explain the difference between a​ single-blind and a​ double-blind experiment. choose the correct answer below. a. in a​ single-blind experiment, the researcher does not know what the response variable is. in a​ double-blind experiment, neither the subject nor the researcher knows what the response variable is. b. a single blind experiment is one in which each experimental unit is randomly assigned to a treatment. a​ double-blind experiment is one in which similar experimental units are grouped together and the experimental units within each block are randomly assigned to treatments. c. in a​ single-blind experiment, the subject does not know which treatment is received. in a​ double-blind experiment, neither the subject nor the researcher in contact with the subject knows which treatment is received. d. in a​ single-blind experiment, there is a control group. in a​ double-blind experiment, there is both a control group and a placebo treatment is used.