Complete question is;
Determine whether the experiment is blind or double blind.
Is the aspirin produced by the World’s Best Pharmaceutical Company better than that of a competitor at relieving headaches? 200 headache sufferers are chosen at random. Migrained Testing Service administers the experiment and provides the results evaluation. Three levels are made: participants receive contents from Bottle A, Bottle B, or Bottle C. Other than the fact that one bottle contains placebo aspirin, no other information is given to the testing service regarding the bottles’ contents.
a) blind study
b) double blind study
C) Neither
Answer:
Double blind study.
Explanation:
We are told that participants receive contents from Bottle A, Bottle B, or Bottle C.
However, the testing service only knows that one bottle contains placebo aspirin but they don't know the other contents nor which of the participants is taking the one with placebo aspirin.
Thus, this is a double blind experiment because neither the participants nor the testing service have knowledge of who is taking the bottle that contains placebo aspirin unlike a blind experiment where the testing service will know which participants got the bottle containing aspirin.