Conrad here is a link you might find useful. <A HREF="http://www.mathworks.com/access/helpdesk/help/techdoc/math_anal/math_anal.shtml" target="_new">http://www.mathworks.com/access/helpdesk/help/techdoc/math_anal/math_anal.shtml</A> There is a good section on curve fitting which is something to avoid when testing investing methods. Irwin