Lecture 5 zToday: More Sections zPlease read these sections. You are responsible for all material in these sections…even those not discussed in class zAssignment #1: Due on Thursday zAssignment #2: Chapter 2: 6…more to come
Two-Way ANOVA zOne-way ANOVA considered impact of 1 factor with k levels (e.g. battery example) zTwo-way ANOVA considers the impact of 2 factors with I and J levels respectively zHave possible treatments for each replicate of the experiment zIf have n replicates, the the experiment has observations
Example: zAn experiment was run to understand the impact of two factors (Table speed and Wheel grit size) on the the strength of the ceramic material (bonded S i nitrate). (Jahanmir, 1996, NIST) zEach factor has two levels (coded -1 and +1 respectively) zThe experiment was repeated 2 times
Data
zModel:
Constraints zSum-to-zero: zBaseline:
Hypotheses
Running the Experiment zTwo-Way ANOVA Model is appropriate for experiments performed as completely randomized designs zThat is, we list the treatments (e.g., 1-8 in the ceramics example) and assign treatments to experiemntal units in random order. zThe trials are in random order
ANOVA Table
Return to Ceramic Data
Interaction Plot
ANOVA Table (S-Plus or R)
zWhat would happen if the experiment was unreplicated (l =1)? zWhat could we do to address this?
Multi-Way (or N-Way) ANOVA (Section 2.4) zCan extend model to more that 2 factors zApproach is the same
Experiment Situation zHave N factors zThe experiment is performed as a completely randomized design zAssumptions: