Error bar example

The following script demonstrates the plotting of error bars. See the figure below.

 X=[0:20]                 ! generate some "data" 
 Y=X^2-20*X+50            !
 YEL=10*RAN(X)            ! lower error
 YEU=10*RAN(X)            ! upper error
 YES=20*RAN(X)            ! symmetric error
 SET PLOTSYMBOL -1        ! set plotting symbol
 WINDOW 5                 ! set window
 SET XLABEL 'Asymmetric errors'
 GRAPH X Y YEL,,YEU       ! plot with asymmetric errors
 WINDOW 6                 ! change windows
 SET XLABEL 'Symmetric errors'
 GRAPH X Y YES            ! plot with symmetric errors
 

  Error bars