Question

A biology group is studying the effect of UV-B on five genotypes of Ailanthus (tree of heaven) taken from an invasive population near Morgantown, WV. They have two levels of UV-B: ambient and high (corresponding to 20% ozone depletion). They grow five seedlings from each genotype of the Ailanthus for 6 weeks under both treatment conditions, then measure biomass at the end of 6 weeks following the treatment(s).

This experiment is a:

(A) one-way factorial design

(B) two-way factorial design

(C) three-way factorial design

(D) 2 x 3-way factorial design

(E) doubly nested design.

Answer 1

Ans. B. Two way factorial design. This is because the single factor UV-B is at two levels namely ambient and high.

We record observations on 5 genotypes by allocating UV-B at both levels to make a comparison.