In 2002, the journal Science reported that a study of women in Finland indicated that having sons shortened the life spans of mothers by about 34 weeks per son, but that daughters helped to lengthen the mothers' lives. The data came from church records from the period 1640 to 1870.
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.