New York Times columnist Paul Krugman (2006) used the idea of correlation in a newspaper column when he asked, “Is being an American bad for your health?” Krugman explained that the United States has higher per capita spending on health care than any country in the world and yet is surpassed by many countries in life expectancy [Krugman cited a study by Banks, Marmot, Oldfield, and Smith (2006), published in the Journal of the American Medical Association]. 

a. Name the “participants” in this study. 

b. What are the two scale variables being studied, and how was each of them operationalized? Suggest at least one alternate way, other than life expectancy, to operationalize health. 

c. What was the study finding, and why might this finding be surprising? If the finding described above holds true across countries, would this be a negative correlation or a positive correlation? Explain. 

d. Some people thought race or income might be a third variable related to higher spending and lower life expectancy. But Krugman further reported that a comparison of non-Hispanic white people from America and from England (thus taking race out of the equation) yielded a surprising finding: The wealthiest third of Americans have poorer health than do even the least wealthy third of the English. What are some other possible third variables that might affect both of the variables in this study? 

e. Why is this research considered a correlational study rather than a true experiment? 

f. Why would it not be possible to conduct a true experiment to determine whether the amount of health care spending causes changes in health?