Numbers in Computer Analysis

In the move analysis I get from the computer analysis here, there's always a number like (-2.63) or w/e in parenthesis.  From what I've gathered so far, it looks like maybe this is some sort of number system that says how likely one of the colors is to win...maybe the larger the positive number the more likley white is to win and the more negative the number the more likely black is to win.

Am I on the right track?  Thanks.

Yes your exactly right

The number roughly relates to how many "pawns" that player has in their advantage.  so a -2.63 advantage is (almost) like saying the black player is winning by (or has a surplus of) 2.63 pawns.  Other things taken into account when calculating this number are the space each player has, open files/ranks and whether or not a player is controlling them with their rooks, potential tactics, whether or not a player has a bishop pair and in what stage of the game, etc.  It's really not a trivial calculation; the main thing is that you know what it means.

Thank you.