/*
   Let's look at the three different scenarios graphically.
*/

#delimit ;
graph twoway (scatter y x)
             (lfit    y x),
  title("Original Data")
  xtitle("X")
  ytitle("Y", orientation(horizontal))
  ylabel(0(5)30)
  ytick(0(1)32)
  xlabel(0(1)10)
  name(g1, replace) nodraw;

graph twoway (scatter y1 x)
             (lfit    y1 x)
             (lfit    y1 x if y1<23, lpattern(dash) lstyle(p1)),
  title("Scenario #1")
  xtitle("X")
  ytitle("Y", orientation(horizontal))
  ylabel(0(5)30)
  ytick(0(1)32)
  xlabel(0(1)10)
  name(g2, replace) nodraw;

graph twoway (scatter y2 x)
             (lfit    y2 x)
             (lfit    y1 x if y1<23, lpattern(dash) lstyle(p1)),
  title("Scenario #2")
  xtitle("X")
  ytitle("Y", orientation(horizontal))
  ylabel(0(5)30)
  ytick(0(1)32)
  xlabel(0(1)10)
  name(g3, replace) nodraw;

graph combine g1 g2 g3, 
  title("Plots of Three Different Data Scenarios") 
  ycommon
  nocopies;
#delimit cr