J
:9. The regression line for a scatter diagram is an
approximation of its graph of averages. For some scatter
diagrams, all of the points of the graph of averages lie on a
straight line. This straight line is then the regression line. 
For other scatter diagrams, the points of the graph of averages
do not all lie on a straight line, and so, of course, they do not
all lie on the regression line. 
+ Now consider the six scatter +J 
diagrams of diagram ? on page ?? of the test. The points of the
graph of averages all lie on the regression line of  <p>

a. all <p>

b. one <p>

c. two <p>

d. three <p>

e. four or five <p>

of the six scatter diagrams. <p>