: <p>

1. r describes the clustering of the scatter diagram around  
   the SD line, relative to the SDs  <p>

:           
       associated with each one-SD increase in x there is an
       increase of only r SDs in y, on the average <p>

3. r determines the accuracy of the regression estimates     
   through the formula for r.m.s. error.  <p>

4. r tells what proportion of the points on the scatter      
   diagram are highly correlated  <p>

Of these four statements, <p>

a. exactly one is true <p>

b. exactly two are true <p>

c. exactly three are true <p>

d. all four are true <p>

e. none are true.