I have a worksheet that imports data from a source. It brings in data for
the past 24-hours. I want to see the last 24 hours, a 4-hour window, and a
1-hr window (not all at the same time).

I have 3 buttons that change a worksheet defined variable (Defined Name) to
the appropriate row value of the data to be graphed.

How do I define the series to use the Defined Name?