In a double-blind study, 50 older adults who had difficulty keeping their balance and/or were slow walkers were randomly assigned to one of three groups. The first group received 4 weeks of training designed to improve balance and walking speed. The second group performed the same physical training but also practiced mental tasks at the same time. They were instructed to give equal attention to the physical and mental tasks. The third group participated in the same activities as the second group but spent half the session focused on the physical tasks and half the session focused on the mental tasks. The researchers concluded that the training methods used for the second and third groups are more effective than the method used for the first group at improving walking speed when an older person is performing a mental task at the same time.
a. Describe the treatment and control groups.
b. Is the study an experiment or an observational study? Explain.
c. What does random assignment mean in this study? How could this be accomplished?
d. Describe the sample and the population.