I just found that topcoder problem archive can not be filtered by probability category. But it has some good practice problems with tutorials for mastering probabilities. Here is the list of some basic and intermediate level problems(div2 500+div1 250) + (div2 100). Problems are in ascending order of points, so you can attempt them in the order they appear in the list.
- http://community.topcoder.com/stat?c=problem_statement&pm=13594
- http://community.topcoder.com/stat?c=problem_statement&pm=11359
- http://community.topcoder.com/stat?c=problem_statement&pm=10878
- http://community.topcoder.com/stat?c=problem_statement&pm=10823
- http://community.topcoder.com/stat?c=problem_statement&pm=10726
- http://community.topcoder.com/stat?c=problem_statement&pm=10033
- http://community.topcoder.com/stat?c=problem_statement&pm=10071
- http://community.topcoder.com/stat?c=problem_statement&pm=8414
- http://community.topcoder.com/stat?c=problem_statement&pm=8016
- http://community.topcoder.com/stat?c=problem_statement&pm=6116
- http://community.topcoder.com/stat?c=problem_statement&pm=5891
- http://community.topcoder.com/stat?c=problem_statement&pm=4487
- http://community.topcoder.com/stat?c=problem_statement&pm=3994
- http://community.topcoder.com/stat?c=problem_statement&pm=2866
- http://community.topcoder.com/stat?c=problem_statement&pm=1778
- http://community.topcoder.com/stat?c=problem_statement&pm=13941
- http://community.topcoder.com/stat?c=problem_statement&pm=13349
- http://community.topcoder.com/stat?c=problem_statement&pm=13085
- http://community.topcoder.com/stat?c=problem_statement&pm=11811
- http://community.topcoder.com/stat?c=problem_statement&pm=11473
- http://community.topcoder.com/stat?c=problem_statement&pm=11510
- http://community.topcoder.com/stat?c=problem_statement&pm=11309
- http://community.topcoder.com/stat?c=problem_statement&pm=10723
- http://community.topcoder.com/stat?c=problem_statement&pm=10289
- http://community.topcoder.com/stat?c=problem_statement&pm=10243
- http://community.topcoder.com/stat?c=problem_statement&pm=9944
- http://community.topcoder.com/stat?c=problem_statement&pm=8590
- http://community.topcoder.com/stat?c=problem_statement&pm=7575
- http://community.topcoder.com/stat?c=problem_statement&pm=7884
- http://community.topcoder.com/stat?c=problem_statement&pm=7822
- http://community.topcoder.com/stat?c=problem_statement&pm=4616
- http://community.topcoder.com/stat?c=problem_statement&pm=3439
- http://community.topcoder.com/stat?c=problem_statement&pm=2234