Question

4) A forester is conducting research at an experiment station on an island in the Caribbean. He is planning a genetic study of a native conifer species that is geographically isolated on the north and south ends of the island. He collects seed cones from 15 trees in both the north and south populations (provenances). Seeds that come from the same tree in the wild represent a family. He plans to evaluate the growth of seedlings from all 30 families in a common garden trial at the experiment station using a Randomized Complete Block Design with 6 blocks. Three seedlings from each family will be grown in a plot in each block, so there will be 30 plots in each block. Circle the statement below that is correct:

a) Families and provenances are cross-classified

b) Families are nested in blocks

c) Seedlings are nested in families

d) Seedlings and blocks are cross-classified

Answer 1

Families can come from both north and south populations (provenances). So, Families and provenances are cross-classified

Three seedlings from each family will be grown in a plot in each block, so there will be 30 plots in each block. So, Families are nested in blocks.

Each seedling and blocks belong to single family. So, Seedlings are nested in families.

Each seedling belongs to a unique block. So, Seedlings and blocks are not cross-classified

The correct statements are,

a) Families and provenances are cross-classified

b) Families are nested in blocks

c) Seedlings are nested in families