In working with his clients and in his lectures at the university, Dr. Ferris tends to explain personality and various psychological disorders in terms of a person's responses being reinforced or punished. Dr. Ferris places the most importance on which theories of personality?

As adults, those who were low-birthweight babies have higher rates of

obesity. malnutrition. normal-range weight. language delays.

People in a hidden population might be more willing to participate in a study if recruited by somebody they know and trust rather than by a researcher. This fact forms the basis of the development of

a. respondent-driven sampling. b. snowball sampling. c. targeted sampling. d. key informant sampling