On Mon, 24 Oct 2011, Simari wrote:
 I am trying to make a linear regression between X (days, 13/06/2011,
 14/06/2011, 15/06/2011 and so on) and Y (price data)
 and look for the slope and R2. 
Unless you have special requirements not mentioned here, the 
place to start is with the "ols" command (/Help/Command 
reference) or the Ordinary Least Squares item under the /Model 
menu.
Allin Cottrell