NOTE: There is not any data for these questions, so no data analysis required.Answer all questions based on the given scenarios.

Experimental Unit: The physical entity to which the treatment is randomly assigned or the subject that is randomly selected from one of the treatment populations (page 35 in our text).

Question 9

Scenario

Current nitrogen fertilization recommendations for wheat included applications of specified amounts at specified stages of plant growth.The recommendations were developed through the use of periodic stem tissue analysis for nitrate content of the plant. Stem tissue analysis was thought to be an effective means to monitor the nitrogen status of the crop and provide a basis for predicting required nitrogen for optimum production.

In certain situations, however, the stem nitrate tests were found to overpredict the required nitrogen amounts.Consequently, the researcher wanted to evaluate the effect of several different fertilization timing schedules on the stem tissue nitrate amounts and wheat production to refine the recommendation procedure.

The researcher created four new fertilization timing schedules that were thought to provide the range of conditions necessary to evaluate the process. The current standard recommendation and a control treatment of no nitrogen were also investigated.

The experiment was conducted in an irrigated field with a water gradient along one direction of the experimental field as a result of irrigation. Since plant responses are affected by variability in the amount of available moisture, it was not possible to have a large number of homogeneous experimental units. However, it was possible to have several groups of plots for this experiment. The statistical consultant recommended four replications to obtain the needed precision.

(a)What is the treatment structure?

(b)List all treatments:

(c)What is the experimental unit?

(d)What is the design structure?