Figure 7.17 shows the birth and death rates for different countries, measured in births and deaths per 1,000 population.

a. Estimate the correlation coefficient and discuss whether there is a strong correlation between the variables.
b. Notice that there appear to be two groups of data points within the full data set. Make a reasonable guess as to the makeup of these groups. In which group might you find a relatively wealthy country like Sweden? In which group might you find a relatively poor country like Uganda?
c. Assuming that your guess about groups in part b is correct, do there appear to be correlations within the groups? Explain. How could you confirm your guess about the groups?

30 25F 20 F E 10 10 20 30 40 0 60 Birth rate (per 1,000)