See the CRC book "Fitting Statistical Distributions: The Generalized
Lambda Distribution and Generalized Bootstrap Methods" by Zaven A.
Karian and Edward J. Dudewicz

It develops the math and provides Maple code for fitting. You will have
to adapt to Excel.

Jerry

Frank & Pam Hayes wrote:

David,

The Tukey-lambda fit looks like it has promise for my cumulative probability
curve, but a google search on Tukey-lambda and Excel was pretty sparse.
Searching on Tukey-lambda alone brought many more results, most of which
were beyond my statistical competance. The cumulative distribution function
shown at : http://www.itl.nist.gov/div898/handb...n3/eda366f.htm
looks to be exactly what I am trying to produce.

Can you point me in the right direction on how I would use Tukey-lambda in
Excel to calculate the cumulative probabilty curve?

Frank

"David J. Braden" wrote in message
...

Another idea:
Generalized inverse Tukey-lambda fit, which requires but 4 parameters, and
is very well behaved at endpoints. The fit is on the inverse cumulative,
and seems to be very stable wrt Excel.

"Jerry W. Lewis" wrote in message
...

And if the data can meaningfully be fitted to an 8th order polynomial, I
would still worry about numerical problems unless you were using Excel
2003 and no coefficients were estimated to be exactly zero
http://groups.google.com/groups?selm...0no_e-mail.com

Jerry

Bernard Liengme wrote:


Use LINEST to generate coefficients - see
www.stfx.ca/people/bliengme/ExcelTips
Use the coefficients to generate trendline data

Do your really have data that can meaningfully be fitted to 8th order?