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Tire Wear Latin Square. Exploratory Design with Orthogonality. Tire Wear Design Layout. Tire Wear ANOVA. Initial Conclusions. Brand does have an effect (tell Marketing if ours is best).
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Tire Wear Latin Square Exploratory Design with Orthogonality
Initial Conclusions • Brand does have an effect (tell Marketing if ours is best). • Car has an effect so it was a good thing your Statistician told you to Block on Car so that variation would not go into error and hide the significance of your results (no layoff). • Position did not have an effect after 5,000 miles (but your mechanic will tell you to rotate your tires every so often anyway).
Oh , and… • Since a Latin Square is an orthogonal design, main effects are not confounded. • In orthogonal designs, Type I and Type III Sums of Squares agree. • In designs where not all combinations of factors are considered, the usual EMS algorithm does not apply.