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Augmented Blocks
Have both replicated and unreplicated treatments
Replicated treatments are tested in each block as in a RCBD
Unreplicated treatments occur in only one block - so each block has a different set of
unreplicated treatments
Advantages
1. Save time and money with smaller blocks
2. Still have critical comparisons
3. Flexible with large numbers of treatments
Disadvantages
1. Less precision for comparing unreplicated treatments
2. Missing data for unreplicated treatment means loss of all information on that
treatment
Uses
1. Preliminary screening and selection of treatments for future experiments
- variety trials
- drug screening
2. Demonstrations
3. Testing extremes of treatment combinations
4. Extra controls, eg assays
Analysis
Extra controls
1. Use regular ANOVA and orthogonal contrasts to compare controls and treatments
2. Use controls as covariate and correct treatment means based on control
measurements.
Extra unreplicated treatments
1. Perform regular ANOVA for replicated treatments
2. Adjust unreplicated treatment means for block effects
Example Experiment
replicated treatments tr = 3
blocks r = 4
unreplicated treatments per block tu = 2
(total of 8 unreplicated treatments)
