Regression Line

The line  of regression  is the  line  which give the best  estimate  to the  values  of one  variable  for any  specific  values  of other  variable.

For two  variables  on regression  analysis there  are two  regression lines. One line as  the regression of X and Y and the other  for regression of Y and X , these  two regression lines  show  the average  relationship  between  the two  variables. The regression  line  of Y on X gives  the most  probable  values  of Y for given values of X  and the  regression  lien of X and Y gives  the most  probable  values  of X for  given  values  of Y.

For  perfect correlation  positive  or negative i ,e, for r= ± the  two lines  coincide i, e,  we will  find only  one straight line. If  r= 0 i, e,  both the variance  are independent then the two  lines will  cut each  other are  a right  angle. In  this case  the two  lines will  be parallel  to x and  y axes. (see figure).