Tosh -
If math analysis software is not convenient, just do it on an Excel spreadsheet.
Choose three cells for the 3 parameters (magnitude normalization, SD, and scale shift) of the Gaussian equation. Then list: x-values in column 1; y-values in column 2; f(x) Gaussian in column 3 using column 1 plus the 3 parameters; finally list the square of the difference y-f(x) in column 4 .
Place the sum of column 4 in another cell and use the <solver> function to minimize it by varying the 3 parameters. For three input points you will get the fit equation. For more input points you will get the LMS fit to the data. (Occasionally, you may have to add constraints in solver.)
Regards -
Robert E. Levin, Ph.D.
Corporate Scientist
OSRAM SYLVANIA
71 Cherry Hill Drive
Beverly, MA 01915, USA
Phone: (978) 750-1594
Fax: (978) 750-1794
e-mail: robert.levin@sylvania.com
-----Original Message-----
From: Tosh Ushino [SMTP:tushino@icnpharm.com]
Sent: Monday, August 14, 2000 1:46 PM
To: Multiple recipients of list
Subject: A question on a simple statistical technique
From: Tosh Ushino@ICN on 08/14/2000 10:45 AM
To: radsafe@romulus.ehs.uiuc.edu
cc:
Subject: A question on a simple statistical technique
Ladies and Gentlemen of RADSAFE,
Back when I was in graduate school, I learned a very simple technique of fitting
three data points into a Gaussian curve. This allowed you to estimate where the
peak was. The part of my brain that stored that information has decayed away.
Does anyone know how to do that, remember what it is called, or can point me to
a text book that describes it?
Thank you in advance.
Sincerely,
Tosh Ushino
--------------------------------------------------------------------------
Toshihide "Tosh" Ushino, CHP Tel: (800) 548-5100 x2413
Product Development Manager Fax: (714) 668-3149
Dosimetry Div., ICN Biomedicals, Inc. Email: tushino@icnpharm.com
3300 Hyland Ave., Costa Mesa, CA USA 92626 tushino@hotmail.com
************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html