Some people claim they can get relief from migraine headache pain by drinking a large glass of ice water. Researchers plan to enlist several people who suffer from migraines in a test. When a participant experiences a migraine headache, he or she will take a pill that may be a standard pain reliever or a placebo. Half of each group will also drink ice water. Participants will then report the level of pain relief they experience.
Read each brief report of statistical research, and identify
a) Whether it was an observational study or an experiment.
If it was an observational study, identify (if possible)
b) Whether it was retrospective or prospective.
c) The subjects studied and how they were selected.
d) The parameter of interest.
e) The nature and scope of the conclusion the study can reach.
If it was an experiment, identify (if possible)
b) The subjects studied.
c) The factor(s) in the experiment and the number of levels for each.
d) The number of treatments.
e) The response variable measured.
f) The design (completely randomized, blocked, or matched).
g) Whether it was blind (or double-blind).
h) The nature and scope of the conclusion the experiment can reach.