Send me (my private email) a sample file with the data.
best wishes
--
Bernard V Liengme
www.stfx.ca/people/bliengme
remove caps from email

"jkeith" wrote in message
...
I understand what you are saying and fully agree, but that is not the
issue.
The equation is just flat wrong UNLESS you set the intercept =0. But doing
that makes the line not fit as well. Any thoughts? Thanks for your time.

"Bernard Liengme" wrote:

It is 'wrong' because the value of y=ax^4+bx^3+cx^2+dx+e if very
sensitive
to the values of the confinements (a, b,....)
You could format the trendline and get more precision and then very
carefully copy the values OR you could you LINEST as shown at
http://people.stfx.ca/bliengme/ExcelTips/Polynomial.htm
best wishes
--
Bernard V Liengme
www.stfx.ca/people/bliengme
remove caps from email

"jkeith" wrote in message
...
fitting a trendline to data and the polynomial equation it spits out is
obviously wrong. Any ideas? thanks