Analysis of Variance

Objective

To decompose the total variance of an experiment into variance attributable to the effects of specific variables.

Examples/Applications

• In-store experiments
• Market tests
• Product tests/concept tests
• Survey order effects
• Picking discriminators in segmentation studies
• Conjoint measurement

Assumptions

• Samples are drawn from normal population
• All samples have the same variance
• Additivity (all means are a function of marginal means and the general mean)

Mechanics

• Total sum of squares
• Between groups sum of squares
• Within groups sum of squares
• Degrees of freedom
• Mean square
• F ratio

Seminal Articles/Texts

• Winer, B.J., "Statistical Principles in Experimental Design", McGraw-Hill 1962

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