We have all seen the commercials where the individual is asked to determine which beverage tastes better. Even given the best controls on the experiment, the experimenter might push one soda closer to the participant, or make sure that one drink is colder than the other. By completing these types of moves, the participant may be skewed which can cause invalid results. To prevent this the experimenter is not told which soda is which. Comparison:
Random assignment:
Control:
Replication:

Is this a blind experiment or a double blind experiment? Why or why not?