Chapter 4, Problem T4.12SPT

(a)

To determine

To identify the experimental units in this experiment.

Answer to Problem T4.12SPT

The experimental units are $72$ selected acacia trees.

Explanation of Solution

The experimental units are a part of the population of which information was actually collected. Thus the experimental units are $72$ selected acacia trees. An experiment deliberately imposes some treatment on individual in order to observe their responses.

(b)

To determine

To explain why it is beneficial to include some trees that have no hives.

Explanation of Solution

It is beneficial to include some trees that have no hives because the sample surveyed for the study should not be a biased one as if we will not include all the trees then the sample will be biased and that will result in wrong estimate. Thus, we want sample that is the representative of all the population.

(c)

To determine

To describe how the researchers could carry out a completely randomized design for this experiment.

Explanation of Solution

  $\begin{array}{l}\text{There are 3 treatments and 72 acacia trees, thus 24 trees }\\ \text{should receive each treatment}\text{.}\\ \text{TREATMENT 1=Active beehive}\\ \text{TREATMENT 2=Empty beehive}\\ \text{TREATMENT 3=No beehive}\\ \text{Assign each tree a unique number between 1 and 72}\text{.}\\ \text{Pick a row from table D}\text{.}\\ \text{Select the first 2-digit number}\text{. If the number is between }\\ \text{01 and 72, then the corresponding tree receives treatment 1, }\\ \text{else move on to the next 2-digit number}\text{.Repeat until 24 }\left(\text{unique}\right)\\ \text{trees have been assigned to receive treatment 1}\text{.Similarly, }\\ \text{select 24 }\left(\text{unique}\right)\text{ trees to be assigned to receive treatment 2 }\\ \left(\text{trees did not receive treatment 1}\right)\text{.}\\ \text{The remaining trees will receive treatment 3}\text{.}\end{array}$