http://www.betangel.com/blog_wp/2013/08 ... ling-data/
I've found that if I add the chance up for all the runners that it usually comes to more than 100%. This doesn't make sense to me though, surely if I use the back odds then the chance should be less than 100%?

Liverpool - 1/1.48 = 0.675675676
Newcastle - 1/8.4 = 0.119047619
The Draw - 1/4.5 = 0.222222222
Total = 1.016945517
Why isn't total 1.0?