CK-12 Foundation
Ck 12: Earth Science: Testing Hypotheses
[Free Registration/Login may be required to access all resource tools.] Learn the steps of how to test hypotheses.
Other
Westgard Qc: Hypothesis Testing
A good description of hypothesis testing. Refers to the null hypothesis as a "straw man" that is either left standing or knocked down. Other links are provided to related parts of the topic.