You can create a plot without having the X's & Y's appear in a worksheet. You can define X and Y as a formula Names. Then reference the names in the series function used to draw the plot on s chsrt
For example:
Create the following names using the Insert:Nameefine command.
Name Refers To:
X ---> ={1;2;3;4;5}
Y ---> =X+X^2
Then the series command will be simillar to
=SERIES(,Book1.xls!X,Book1.xls!Y,1)