(a) Prove that Var(𝜏⋅j − 𝜏⋅i)=(2k∕𝜆t)𝜎2 in a BIBD. (b) If the experiment were run as a randomized complete block, Var(𝜏⋅j − 𝜏⋅i) would equal Var(ȳ⋅j − ȳ⋅i) = 2𝜎2∕b. Prove that 2k∕𝜆t > 2∕b...

(a) Prove that Var(𝜏⋅j − 𝜏⋅i)=(2k∕𝜆t)𝜎2 in a BIBD.

(b) If the experiment were run as a randomized complete block, Var(𝜏⋅j − 𝜏⋅i)

would equal Var(ȳ⋅j − ȳ⋅i) = 2𝜎2∕b. Prove that 2k∕𝜆t > 2∕b and give a

statistical interpretation.