First of all, use an XY chart, not a Line chart.
In algebra we learned that the equation of a line is Y=mX+b. m is your
initial slope, b is the value of Y where X is zero. If you planned it so the
phenomenon you're monitoring starts at (0,0), then b is zero, so you need to
plot a series with two points, (0,0) and (Y,X), where Y=mX. pick an
appropriate value for X so the line stays in the chart. Put the data into
the sheet like this:
0 0
X Y <-- your calculated values
Copy this range, select the chart, and use Paste Special to add the data as
a new line, with series in columns and category labels (X values) in the
first column.
- Jon
