In a study of the effectiveness of an experimental drug on sleep apnea, researchers are expecting the drug to have long-lasting beneficial effects on their participants. In this case, what type of correlated-groups design should they use?

Quasi-experimental designs are different from low-constraint methods in that

A) quasi-experimental methods attempt to answer questions of causality. B) low-constraint methods attempt to answer questions of causality. C) unlike low-constraint methods, quasi-experiments always directly manipulate the independent variable. D) unlike low-constraint methods, quasi-experiments usually assign participants randomly to groups.

For much of the 19th century, the model of the relationship between states and nation in the United States was one of ______.

a. coercive federalism b. unitary federalism c. dual federalism d. cooperative federalism