Crowdedness. In a Chance magazine article (Summer 2005), Danielle Vasilescu and Howard Wainer used data from the United Nations Center for Human Settlements to investigate aspects of living conditions for several countries. Among the variables they looked at were the country’s per capita gross domestic product (GDP, in $) and Crowdedness, defined as the average number of persons per room living in homes there. This scatterplot displays these data for 56 countries:
a) The value of Kendall’s tau is -0.626. What does this tell us about the association?
b) The value of Spearman’s rho is -0.804. What does this tell us about the association?
c) What about these data would make the nonparametric measures appropriate choices?