:3. Diagram ? on page ? represents a scatter diagram each point
of which represents the IQ scores of a married couple. The
x-coordinate of a point represents the husband's IQ, while the
y-coordinate represents the wife's IQ. The dashed line is the SD
line.  One of the following statements is correct.  Which one? <p>

a. The regression line for the husband's IQ from the wife's  
   IQ is the same as the regression line for the wife's IQ 
       from the husband's IQ, and both are equal to the dotted
       line. <p>

b. The regression line for the husband's IQ from the wife's  
   IQ is the same as the regression line for the wife's IQ 
       from the husband's IQ, and both are equal to the solid
       line. <p>

c. The regression line for the husband's IQ from the wife's  
   IQ is the dotted line, while the regression line for the  
   wife's IQ from the husband's IQ is the solid line.  <p>

d. The regression line for the husband's IQ from the wife's  
   IQ is the solid line, while the regression line for the   
   wife's IQ from the husband's IQ is the dotted line.