TREND is a built-in worksheet function. (You don't need Analysis ToolPak to
use it.) To go beyond linear regression, you could use xdata^{1,2,3} as the
x-data range in TREND, array-entered using Control+Shift+Enter.

The Regression tool of the Analysis ToolPak will perform polynomial
regression if you use x, x^2, and x^3 values (adjacent columns on a
worksheet) as the X-range.

Or, construct an XY (Scatter) chart with some hypothetical Y values, and use
Add Trendline (polynomial of order 3) to get a smooth curve approximately
through the points.

- Mike

www.mikemiddleton.com

"Jim Thomlinson" wrote in message
...
You can try the Trend function. You will need the analysis tool pack. It
will
perform a polynomial regression on a set of values.

HTH

"Adam" wrote:

I want to spread a value over a range of dates as an "S-Curve" with the
ability to skew the distribution. What is the best way of doing this,
please?