1. Designing Experiments
Section 5.2

2. Experimental Units Individuals on which the experiment is done
If the individuals are human then we call them subjects

3. Treatment
A specific experimental condition applied to the units (subjects)

4. Factors
Explanatory variables in an experiment

5. Note: Experiments can give good evidence for causation
They allow specific factors to be studied
They study the combined effects of several factors

6. Placebo Effect
Response to a dummy treatment

7. Control Group
Group that receives the placebo

8. Principles of Experimental Design
Control
Randomize
Replicate

9. Statistically Significant
An observed effect so large it would rarely occur by chance

10. Completely Randomized
When all experimental units are allocated at random among all treatments

11. Cautions About Experimentation

12. Lack of Realism
Subjects, treatments, or setting of an experiment may not realistically duplicate the conditions

13. Double-blind Experiment
Neither the subjects nor the people who have contact with them know which treatment a subject received

14. Randomized Comparative Experiment
One of the most important ideas in statistics
Able to give convincing evidence for causation

15. Matched Pairs Design Compares 2 treatments
Blocks of 2 units that are as closely matched as possible
Randomize the order for each subject
Example of block designs

16. Block
A group of experimental units or subjects that are known before the experiment to be similar in some way that is expected to affect the response to the treatments
A form of control

17. Block Design
Random assignment of units to treatments is carried out separately within each block
Matched pairs is a form of block design

18. Practice Problems
pg. 306 #