I'm experiencing an issue with a chart, I've just created a simple report, the thing is this report shows 4 different values and they are working properly.
Also I've just created a variable which takes an average between those 4 values.

So I would like to create a chart to show this average between those values instead showing only the results.
And I can´t do it yet.
Can someone give me some help on this?

Thanks in advance.
Marcos.