Orthogonal block design
= Orthogonal block design
{title2=$n_{ij}=r_i k_j/n$}
An <orthogonal block design> has centered treatment-indicator vectors <orthogonal> to centered block-indicator vectors on the <experimental units>. With treatment replication $r_i$, block size $k_j$ and total $n$, this is equivalent to $n_{ij}=r_i k_j/n$. It permits additive block adjustment without changing treatment estimates.