1. Copyright ©2013, 2010, 2007, 2004 by W. H. Freeman and Company The Basic Practice of Statistics, 6 th Edition David S. Moore, William I. Notz, Michael A. Fligner Figure 9.1 Confounding: we can’t distinguish the effects of drinking habits from the effects of overall diet and lifestyle.

2. Copyright ©2013, 2010, 2007, 2004 by W. H. Freeman and Company The Basic Practice of Statistics, 6 th Edition David S. Moore, William I. Notz, Michael A. Fligner

3. Copyright ©2013, 2010, 2007, 2004 by W. H. Freeman and Company The Basic Practice of Statistics, 6 th Edition David S. Moore, William I. Notz, Michael A. Fligner Figure 9.2 The treatments in the experimental design of Example 9.3. Combinations of values of the two factors form six treatments.

4. Copyright ©2013, 2010, 2007, 2004 by W. H. Freeman and Company The Basic Practice of Statistics, 6 th Edition David S. Moore, William I. Notz, Michael A. Fligner Figure 9.3 Outline of a randomized comparative experiment to compare online and classroom instruction, for Example 9.5.

5. Copyright ©2013, 2010, 2007, 2004 by W. H. Freeman and Company The Basic Practice of Statistics, 6 th Edition David S. Moore, William I. Notz, Michael A. Fligner Figure 9.4 Outline of a completely randomized design comparing three energy-saving programs, for Example 9.6.

6. Copyright ©2013, 2010, 2007, 2004 by W. H. Freeman and Company The Basic Practice of Statistics, 6 th Edition David S. Moore, William I. Notz, Michael A. Fligner Figure 9.5 Outline of a block design, for Example 9.10. The blocks consist of male and female subjects. The treatments are three advertisements for the same product.