Consider a BIBD (Balanced Incomplete Block Design) where the total number of blocks (b) is 50, each of which has 10 treatments (k). Moreover, each treatment (v) occurs in 25 of the blocks (r). If each pair of treatments occurs together in exactly 5 blocks (λ), which equation must necessarily be true?
1
bk = r(v - 1)
2
λ(v - 1) = r
3
bk = vr
4
rλ = k(v - 1)