Fixed and Random Effects in Analysis of Variance
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This theory explores how to determine appropriate F-tests for expected mean squares in ANOVA, including coefficients and interactions to consider, with detailed examples. It covers fixed and random effects, pooling sums of squares, and multiple comparisons.
Fixed and Random Effects in Analysis of Variance
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Presentation Transcript
Theory of Analysis of Variance [e2 + kt2]/e2 = 1, if kt2 = 0
Expected Mean Squares • Dependant on whether factor effects are Fixed or Random. • Necessary to determine which F-tests are appropriate and which are not.
Setting Expected Mean Squares • The expected mean square for a source of variation (say X) contains. • the error term. • a term in 2x. • a variance term for other selected interactions involving X.
Coefficients for EMS Coefficient for error mean square is always 1 Coefficient of other expected mean squares is # reps times the product of factors levels that do not appear in the factor name.
Expected Mean Squares • Which interactions to include in an EMS? • All the factors appear in the interaction. • All the other factors in the interaction are Random Effects.
Example • Ten yellow mustard lines. • Five different nitrogen levels (50, 75, 100, 125, 150 units of N). • Three replicates. • Raw data presented in Table 7 (Page 110 & 111)
Another Example • Four species of Brassica. • Ten lines within each species. • Three insecticide treatments (Thiodan, Furidan, none). • Three replicates. • Raw data in Table 8.