ERRORBAR

        [GREG1\]ERRORBAR Argument [Array_X Array_Y Array_Z [Orientation]]

    This command draws error bars on  all (X,Y) points (read by COLUMN X and
    Y,  or  specified  in  Array_X  Array_Y)  of  length read by COLUMN Z or
    specified by Array_Z.  Argument may be  +X X -X  +Y Y or  -Y.  Symmetric
    errorbars  are  drawn  if  you  do  not specify the sign, while only the
    errorbar of  the  given  sign  is  drawn  if  you  do  so.  This  allows
    independent  errorbars  in  opposite directions. The size of the line at
    the end of the errorbar is the Marker size and can therefore be adjusted
    with SET MARKER.

    Errorbars with arbitrary orientation can be obtained by specifying  code
    +O,  O  or  -O.  The orientation (in degrees) is then either read from a
    fourth array if one is specified on the command line, or otherwise taken
    from the current marker orientation (as specified in SET ORIENTATION).