:1.  Diagram ?? has two panels, each of which represents a
scatter diagram. The panel on the left represents income and
education for individuals in three geographic regions, labelled
A,B,C. Each individual is marked by the letter showing his region
of residence. The panel on the right shows the averages for each
region. This shows that one must be cautious about ecological
correlations (correlations based on rates or averages) because <p>

a. such a correlation can ruin a perfectly good bowl of      
   alphabet soup.  <p>

b. a correlation based on individuals may be only moderate,  
   while one based on averages may be close to 1. 
 
 	
 c. an ecological correlation can be excessively beneficial to
   the enviroment.  <p>

d. as shown by the two panels, a correlation based on        
   averages may be only moderate, while one based on         
   individuals may be close to 1.  <p>

e. replacing individuals by averages doesn't affect the      
   correlation coefficient.  <p>

: Exactly 1 of the five choices a,b,c,d, and e results in a
true statement.