Chapter 11, Problem 33E

21–34. What’s the design? 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.

33. Athletes who had suffered hamstring injuries were randomly assigned to one of two exercise programs. Those who engaged in static stretching returned to sports activity in a mean of 15.2 days faster than those assigned to a program of agility and trunk stabilization exercises. (Journal of Orthopaedic & Sports Physical Therapy 34:3)