Which of the following variants of liberalism places the most emphasis on organizations like the United Nations in helping foster peace?

________________ of participants is done to obtain a representative sample, and __________ of the participants is done to improve the experimental design of the study

a. Random selection; random assignment b. Random selection; random sampling c. Random assignment; random selection d. Random assignment; matching

When the Clear Air Act was revised in 1990 it gave states _____ to comply

A) 6 months B) 5 years C) 20 years D) 1 week E) 1 year