# Additive Model on Two-Way Layout

An experiment involving one-way layout with blocks is called bf randomized block design for which agricultural experiments provide a classic example. To compare the effects of different fertilizers (``treatments,'' or ``factor levels''), plots of land (or ``blocks'') are selected, and each of them is divided into plots; this is viewed as a multi-sample generalization of paired experiment. Within each block, the assignment of fertilizers to plots is made at random, which helps to ensure against unintentional bias. Then data of size are obtained for each combination of treatment and block, and summarized in the following table.

Treatment | Block-1 | . . . . . . . | Block-b | Sample size |

1 | . . . . . . . | |||

. . . . . . . | ||||

k | . . . . . . . |

Each consists of measurements , .

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