1. HARRIS COUNTY WATERSHED PROTECTION GROUP Lessons Learned on Storm Water Quality Research Projects Presented by: Trent Martin July 15, 2008

3. Statistical Significance – Our “Holy Grail”

4. POWER

5. Statistical Significance – Our “Holy Grail” POWER Things that affect POWER: * variability

6. Statistical Significance – Our “Holy Grail” POWER Things that affect POWER: * variability * level of significance

7. Statistical Significance – Our “Holy Grail” POWER Things that affect POWER: * variability * level of significance * size of difference between sets

8. Statistical Significance – Our “Holy Grail” POWER Things that affect POWER: * variability * level of significance * size of difference between sets * number of samples collected

9. Quality Assurance Project Plan (QAPP)

10. It’s OK to ask for help!

11. K.I.S.S. - Keep it simple. Answer one question at a time.

14. Any Questions? For more information: Harris County Watershed Protection Group (713) 290 - 3000 or www.CleanWaterways.org Physical Address: 9800 Northwest Frwy., Suite 305, Houston, TX 77092