In the early 1970s, Pakistan secretly passed messages between China and the United States, leading to a breakthrough in relations between those two nations. This illustrates the concept of __________.

One of the major potential confounding factors in a simple pretest-posttest study is

A) placebo effects. B) frustration effects. C) effects due to the treatment. D) regression to the mean.

In the Slaughter-House Cases (1873), the Supreme Court ruled

A) that the "privileges and immunities" clause of the Fourteenth Amendment did not protect citizens from discriminatory actions by state governments. B) that separate facilities were acceptable as long as they were equal. C) that all forms of segregation are unconstitutional. D) that the literacy test is acceptable. E) that juries cannot be all of one race.