1.A(n) __ is one in which some or all information is withheld from a subject, the investigator, or both.
2. Conducting an experiment one time is called a(n) __.
3. A(n) __ is a test in which scientists do not change or control variables.
4. A(n) __ is a decision based on the results of an experiment.
PLEASE USE THESE WORDS: trial, conclusion, observational study, blind experiment, theory, hypothesis