Hey DrKittenPaws.

Pretty much any book on introductory university statistics will have a tonne of problems for you to work on.

If you have access to a university library, go to the statistics section and look for books like these:

Mathematical Statistics with Applications: Dennis Wackerly, William Mendenhall, Richard L. Scheaffer: 9780495110811: Amazon.com: Books

Introduction to Mathematical Statistics: Robert V. Hogg, Allen Craig, Joseph W. McKean: 9780130085078: Amazon.com: Books