STA 6166 UNIT 5 Section 1
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Section 1

Design Concepts for Experiments and Studies

Readings Ott and Longnecker, Chapter 15, pages 829-852.
Instructor Guidance

This is a short chapter but don't be fooled. There is a lot of important concepts introduced here. Pay attention to the following:

  • The difference between observation and experimental studies.
  • The difference between the two methods of controlling crucial factors in experiments.
  • The list of items that should be included in a experimental plan.
  • The definition of treatment and factor. Can you give examples from your field of study at to what is a factor and what is a treatment?
  • Can you give an example of a factorial set of treatments?
  • What is a control treatment and why is it important in most experimental studies.
  • What is an experimental unit? How is it different from the measurement unit?
  • What do we mean by replication of a treatment in an experiment?
  • Is "experimental error" really a mistake?
  • What is the important role of the measurement of the variance of the experimental error (OK - I prefer to use the term residual)?
  • What do we mean when we talk about "control"?
  • What is a block, and why is it an important tool in experimental design?
  • What is a covariate?
  • Does it make a difference if we talk about randomizing treatments to experimental units or randomly assigning experimental units to treatments?
  • Do you understand how to do this randomization?
  • What is the difference in randomization between a completely randomized design and a randomized complete block design?
  • If I have more experimental units in a block than I have treatments, what do I do about randomization?(see page 844)
  • Do you understand how to use the equation for number of replicates on page 845?

Answers to all these questions are in this chapter.

PPT Lecture Experimental Design Notes included in Unit 5 Section 2 lecture slides on Randomized Complete Block Design.
Optional Activities None
Exercises To check your understanding of the readings and practice these concepts and methods, go to Unit 5 Section 1 Exercises, do the exercises then check your answers from the page provided. Following this continue on to the Unit 5 Section 2.