22 - Experimental Design

Is it ever possible to get convincing evidence of a cause-and-effect relationship?

Practice

Chapter 13 # 7, 21, 23, 32,33,43, Read pages 294-309

Vocabulary

subject, experimental unit, levels of a factor, treatment, control, control group, replicate, block, randomly assign, blinding, placebo, matching, two factor experiment, confounding

Study Questions

  1. What are the basic principles of experimental design?
  2. Is it important to select random individuals to be in our experiment? Explain where and why randomization is important.
  3. What is the point of replication in an experiment and replication of an experiment?
  4. What is the importance of a control group and the placebo?
  5. When and why should blinding / double-blinding be used in experiments?
  6. What is the purpose of blocking?
  7. What is a completely randomized experiment?
  8. When can we say that the results of our experiment are statistically significant?

Resources

  1. Link: Salk Polio Trials article link
  2. Slide Deck: 22-Experimental-Design.pdf