Factor 1 25%=0.25
Factor 2 15%=0.15
Factor 3 12%=0.12
Factor 4 8%=0.08
etc

Rating=1-(1-0.25)(1-0.15)(1-0.12)(1-0.08) ... etc

=1-0.75*0.85*0.88*0.92 ... etc

=1-0.51612 for these four example factors

=0.48388 or 48% (to nearest whole number)

This means there is a 48% chance of at least one of the factors producing a winner.

I like to keep things simple. I only use two factors at present and my results agree with the theory. Of course getting a good price is another matter.

gunny72