Poor school performance is associated with risk behaviors

Dr. Land conducted a study in a preschool to test his hypothesis that the amount of unstructured time (free play) in a day affects the amount of unruliness that children display

Teachers systematically varied the amount of free play each day for a month, and Dr. Land's research assistants recorded the amount of unruliness children displayed each day. This study would best be described as a(n) a. correlational study. c. field experiment. b. laboratory experiment. d. quasi-experiment.

Theories differ from mere opinion and belief in that

A) they provide the ultimate truth. B) they are usually too abstract to be used as a basis for practical action. C) they cannot be tested in a research setting. D) their continued existence depends on scientific verification.