Confused with Optimization results

[b519b@xxxx]

To those with wiser heads than mine:

Up till now, I have had no difficulty interpreting optimization 
results, but my optimization has been fairly straight-forward since 
I just studied strategies on one stock at a time over years of buy 
and sell signals. For these studies, I found 4 columns on the 
optimization report most useful: Net%Profit and RAR along with a 
comparison of the #winners and #loosers columns. 

But now I am doing optimization in a new way and am very confused. 
Instead of testing 1 stock over multiple buy and sell periods, I am 
testing 600 stocks over a single buy period. The optimization steps 
are designed to segment the stocks into groups of about 60 each and 
report the results. I had hoped this would let me understand an 
interesting time period more fully and allow me to identify clusters 
of low risk with reasonable profits. However, some of the columns I 
used in the past seem to go crazy now. For example, the Net%Profit 
column often reports 1% to 5% profitability even when the winners 
outnumber the looser trades and when the average gain colume reports 
a 25% average gain per trade. My guess is the 90% of the stocks that 
are not bought are including when calculating the Net%Profit. That 
also seems to be the case for the Exposure column which is often 
below 10%. And the RAR column will can give astronomically high 
numbers if the Exposure column is gets below 5%. In short, I know I 
should be looking at other columns -- unless there is an option to 
select that will exclude stocks not purchased when calculating the 
above columens. Is there such an option?

So I am looking at other columns instead. Am I on the right track to 
be concentrating on the following columns and is my interpreation of 
them correct. I have read the AB documentation, but I still have 
some questions: 

1. AvgWin/AvgLoss column: This I assume divides the avg gain in 
dollars by the average loss in dollars. 

2. #winners and #loosers: I look at the ratio between these two.

3. Avg Trade: This column appears to give the average PROFIT in 
DOLLARS for all the trades. Since I would find a percentage number 
to be more understandable, I set the Initial Equity to 100 on the 
system settings screen. But does this affect the results if a 
stock's price is 51$? In such a case, does AB buy 1.98 shares or 
just 1 share? Am I misleading myself by trying to get this column to 
give percentage results.

4. Profit factor: This appears to combine the results of the 
AvgWin/AvgLoss column with the ratio of #winners to #loosers. If my 
interpretation is correct, this is a very useful column since it 
gives an idea of the system's profit to risk characteristics. 
However, it sometimes gives no results if there happen to be no 
loosing stocks in an optimization step. 

Am I looking at the right columns? Am I misinterpreting any?

Thanks in advance for any comments.

b