I am trying to fit a non-linear formula to a set of data in Excel 2007. I
use the trendline feature and have selected several different formulas. On
my chart, the trendline matches my data very well.

But, the formula that is displayed does not mathematically fit my data at
all. When I place in my variables into the formula Excel provided, my
predicted values are way off the chart.

What am I doing wrong and how do I fix this?

1. Use a scientific number format with lots of places (15) to make sure you
see all digits of the calculated trendline.
2. Make sure it's an XY chart, not a Line chart.

- Jon
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Jon Peltier, Microsoft Excel MVP
Tutorials and Custom Solutions
Peltier Technical Services, Inc. - http://PeltierTech.com
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"John1791" wrote in message
...
I am trying to fit a non-linear formula to a set of data in Excel 2007. I
use the trendline feature and have selected several different formulas.
On
my chart, the trendline matches my data very well.

But, the formula that is displayed does not mathematically fit my data at
all. When I place in my variables into the formula Excel provided, my
predicted values are way off the chart.

What am I doing wrong and how do I fix this?

Thank you,

I was using a line chart and not XY, seems to work now.

-John