Thank you very much for the kind help ! It works ! An important point is we should not forget "with(plots)" command at the top ! So, now one can plot everything without using Matlab ! 

Thank you very much for the kind help ! It works ! An important point is we should not forget "with(plots)" command at the top ! So, now one can plot everything without using Matlab ! 

Thank you for the helpful tip ! I have checked that it works in Maple 15. But I found some more detailed questions. (1) How can I plot some (analycic) function on the data plot with error bars with the "ErrorPlot" command ? It seems to be hard to use both "plot" and "ErrorPlot" command.  (2) Can I change the symbol in the ErrorPlot ? The defaut symbol is the circle.  

Thank you for the helpful tip ! I have checked that it works in Maple 15. But I found some more detailed questions. (1) How can I plot some (analycic) function on the data plot with error bars with the "ErrorPlot" command ? It seems to be hard to use both "plot" and "ErrorPlot" command.  (2) Can I change the symbol in the ErrorPlot ? The defaut symbol is the circle.