In a study of television's influence on children, researchers analyzed standardized test results and television viewing habits of1700 children.They found that children who averaged more than2 hoursof television viewing per day when they were younger than 3 tended to score lower on measures of reading ability and short-term memory.

(a) Is the study described an observational study or an experiment?

a. an observational study

b. an experiment

(b) Is it reasonable to conclude that watching two or more hours of television is the cause of lower reading scores?

a. Yes, it is a reasonable conclusion.

b. No, the conclusion can't be made.

c. There is not enough data to decide.

The article"Acupuncture for Bad Backs: Even Sham Therapy Works"summarized a study conducted by researchers at the Group Health Center for Health Studies in Seattle. In this study,638 adults with back pain were randomly assigned to one of four groups. People ingroup 1received the usual care for back pain. People ingroup 2received acupuncture at a set of points tailored specifically for each individual. People ingroup 3received acupuncture at a standard set of points typically used in the treatment of back pain. Those ingroup 4received fake acupuncturethey were poked with a toothpick at the same set of points chosen for the people ingroup 3!

Two notable conclusions from the study were: (1) patients receiving real or fake acupuncture experienced a greater reduction in pain than those receiving usual care; and (2) there was no significant difference in pain reduction for those who received acupuncture (at individualized or the standard set of points) and those who received fake acupuncture toothpick pokes.

(a)

Is this study an observational study or an experiment? Explain.

a. This is an experiment since there were four groups.

b. This is an experiment since it was decided by the researchers which participants would receive which treatments.

c. This is an observational experiment since one of the treatments was fake.

d. This is an observational experiment since they were observed while receiving the care.

(b)

Is it reasonable to conclude that receiving either real or fake acupuncture was the cause of the observed reduction in pain in those groups compared to the usual care group? What aspect of this study supports your answer? (Hint: Look atTable 2.1.)

a. Yes, this is a reasonable conclusion since the participants were randomly assigned to the treatments.

b. No, this is not a reasonable conclusion since one of the groups received fake treatment.

c. Yes, this is a reasonable conclusion since one of the groups received fake treatment.

d. No, this is not a reasonable conclusion since the participants were randomly assigned to the treatments.