Chapter 4.2, Problem 71E

(a)

To determine

To describe a randomized block design for this experiment and also justify your choice of block.

Explanation of Solution

In this study, a citrus farmer wants to know which of three fertilizers (A, B, and C) is most effective for increasing the number of oranges on his trees. He want to do an experiment with a randomized block design.

A randomized block design can group the subjects into blocks which have a common characteristic and thus a randomized block design allows us to take into account the change of one or more extra variables.

The farmer wants to test the three fertilizers for the effectiveness of the oranges on his trees. Thus the various sizes of mature trees can be used as the blocks for the experiment. Thus, randomized bock experiment can be conducted.

(b)

To determine

To explain why a randomized block design might be preferable to a completely randomized design for this experiment.

Explanation of Solution

In this study, a citrus farmer wants to know which of three fertilizers (A, B, and C) is most effective for increasing the number of oranges on his trees. He want to do an experiment with a randomized block design.

A randomized block design might be preferable to a completely randomized design for this experiment because randomized block design can group the subjects into blocks which have a common characteristic and thus a randomized block design allows us to take into account the change of one or more extra variables.

Thus we can then best use blocks based on how overweight the subjects are, because the alphabetical order has no interesting characteristics that we want to investigate.