Split plot and Nested Designs

 A split-plot design is defined as one factor assigned at the level of main plots (water or none), which are then subdivided into subplots that are the level of replication for a second factor (corn type). A nested design is defined as a research design in which levels of one factor are hierarchically subsumed under levels of another factor. As a result, assessing the complete combination of A and B levels is not possible. Like a split plot design, replication differs for different factors within the same experiment. However, in a nested design each level of one factor is NOT crossed with all levels of the other factor. An example we could use to understand this is to compare differences between 6 cities, 3 on the west and 3 on the east. We can’t analyze the interaction between city and coast because Boston is only on the east coast, Seattle is only on the west.