Which of the following is measured by comparing pretests to posttests?

Naturalistic observation and case-study research allow us to

A) identify contingencies B) prove causality C) manipulate the independent variable D) rule out alternative hypotheses.

Which of these statements would make the best argument for a progressive system of taxation?

a. Workers are entitled to keep the money earned by their labor. b. Efficiency and freedom are more important than equity and security. c. Government intervention in the economy inevitably leads to a loss of productivity. d. The government has a responsibility to ensure that every citizen enjoys a basic level of subsistence.