Depends a lot on the specifics of your data set.

1) If your data can be fit to a straight line, you could use a chart
trendline, or the SLOPE or LINEST worksheet functions to obtain the
overall rate of change of the data set.

2) If a straight line won't readily fit your data, then you have
several options, none of which are "built in" type functions. You
could fit your data to a reasonable curve (using a trendline or LINEST
or other technique) and then use calculus to determine the derivative.

Or you could select any two points and estimate the slope by using the
SLOPE function on those two point, or use the formula
slope=(Y2-Y1)/(X2-X1).

Does that help?


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MrShorty
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