I think the .5 in a betting line means that a team that's favored by 3.5 points needs to win by 4 for you to win money at the window. The point spreads in football, for instance, are set by the way the public tends to put the money and will go up and down depending on how much $$$$ is wagered on both sides. For instance, if the Packers are favored to beat the Bears September 13th by 3 points at the start of the week, and if there's a lot of $$$$ on the Bears, the spread will likely move towards Chicago. If there's more $$$$ on the Packers, the number will likely go higher towards Green Bay. One thing's for sure...That half point hook will get you every time.

I don't have it in front of me right now, but if memory serves, the difference between 3 and 3.5 is something like 35 cents (-110 to -145). 7 to 7.5 is something like 15 cents. 2.5 to 3 and 6.5 to 7 are also pretty important half points. The others are more insignificant, but still not valueless. I'll try to find the chart.

I think the .5 in a betting line means that a team that's favored by 3.5 points needs to win by 4 for you to win money at the window. The point spreads in football, for instance, are set by the way the public tends to put the money and will go up and down depending on how much $$$$ is wagered on both sides. For instance, if the Packers are favored to beat the Bears September 13th by 3 points at the start of the week, and if there's a lot of $$$$ on the Bears, the spread will likely move towards Chicago. If there's more $$$$ on the Packers, the number will likely go higher towards Green Bay. One thing's for sure...That half point hook will get you every time.

http://www.sbrforum.com/Betting+Tools/Half+Point+Calculator.aspx