[libreoffice-users] intercept and slope -- is there a problem?

If I use a small amount (3 pairs) of dummy information, the intercept, 
slope and R^2 are exactly what I expect them to be.  If I use something 
on the order of 400 pairs it makes no sense at all.  When I use Linest, 
the results are reasonable.

I am evaluating stock trading systems against holding the market.  The 
data pairs are the monthly percentage change in the model vs. the 
market.  A regression produces the y-intercept (called alpha), the slope 
(called beta) and R^2.

Generally, if I know the total return for the model and the market the 
calculation

   "total model return" = "total market return" * beta + alpha
      or
   y = mx + b

is fairly close if I get the results from linest.  They are way off from 
intercept and slope.

If the dependent variable is in A and the independent in B and there are 
400 pairs, I can use INTERCEPT|SLOPE(A1:A400; B1:B400).  The results 
aren't even close and I don't know why.  Plugging the average returns 
for the market into the equation to calculate the expected return for 
the model produces nothing reasonable.

Any ideas?  I am probably missing something really obvious.


-- 
For unsubscribe instructions e-mail to: users+help@global.libreoffice.org
Problems? http://www.libreoffice.org/get-help/mailing-lists/how-to-unsubscribe/
Posting guidelines + more: http://wiki.documentfoundation.org/Netiquette
List archive: http://listarchives.libreoffice.org/global/users/
All messages sent to this list will be publicly archived and cannot be deleted