Three important principles of experimental design are: A designed experiment is a study in which there is an intervention by the experimenter to impose treatments on the experimental units - look over Example 2.1… treatments are combinations of levels of the factors. The response is measured for each unit and comparisons are made between the treatments … often the treatment groups are compared with a control treatment (or a control). Three important principles of experimental design are: randomization control replication

Review the first example in section 2.5: The experimental unit might be different from the measurement unit, the physical entity on which the response is measured… see Ex. 2.2 The experimental error is “the variation in the response among expermental units assigned the same treatment and observed under the same conditions Review the first example in section 2.5: p.26: “… evaluate the wear characteristics of 4 major brands of tires.” factor(s)=?; levels=?; treatment(s)=?; response=? what are the “controlled variables” or “extraneous factors” that are the same for all brands of tire? there are many possible designs

randomly assign a brand of tire to a car… randomly assign 4 tires to a car…but see Tab.2.1 block by car and randomize the brands Tab. 2.2 block by car and position on the car and randomized the brands Tab. 2.3 (Latin Square) Look at example #2 (p.29) “…examine the effects of temperature and humidity on the bonding strength of the new adhesive” factors? levels? blocks? treatments? response? replications? experimental and measurement units?

Look at the one-at-a-time approach to factorial designs vs Look at the one-at-a-time approach to factorial designs vs. the full factorial treatment structure HW: Work through exercises 2.6-2.9 for next time. Make sure you understand the terminology in this chapter…