A study looked at World Bank data on the political stability and economic growth of countries in the world. It found that more politically stable countries experienced more economic growth. Which of the following is the unit of analysis in this study?

Federal law prevents a state from closing voter registration more than __________ before a federal election

a. 15 days b. 30 days c. 2 months d. 6 months

In evaluating a nutritional breakfast program for children in poverty, randomly assigning children to breakfast/no-breakfast groups

A) will create clear statistical problems. B) will create data that are uninterpretable. C) is an ethical problem. D) should always include a repeated measures component.