You can use another cell that has a formula which does the subtraction for
you. You can only use link formulas, not calculation formulas, in the edit
boxes where you enter a range for a chart element.

- Jon
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Jon Peltier, Microsoft Excel MVP
Peltier Technical Services, Inc.
http://PeltierTech.com/WordPress/
_______


"rolando" wrote in message
...
I have 1 serie with 20 datapoints, defined as line-type graph
A 2nd series represent the average of all 20 datapoints an is located at
position 20 on the X-axis, defined as scatter-type
I want to draw a line from this point towards the Y-axis, to mark the
average.
For this I use the X-error bar with a fixed value of 19; 20 cannot be used
because the Y axis would shift 1 tick mark to the right (?)
The number of datapoints is growing (here 20) and is located in a
particular
cell. Can I use this ref as custom error bar value but minus 1 so I don't
have to change the value every time the number of datapoints is increasing
?