The May 4, 2000, issue of Science News reported that, contrary to popular belief, depressed individuals cry no more often in response to sad situations than nondepressed people. Researchers studied 23 men and 48 women with major depression and 9 men and 24 women with no depression. They showed the subjects a sad film about a boy whose father has died, noting whether or not the subjects cried. Women cried more often than men, but there were no significant differences between the depressed and nondepressed groups.
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.