An agricultural research scientist is interested in determining an appropriate amount of nitrogen for a newly developed soybean fertilizer. This researcher is considering four amounts of nitrogen: 60 lbs/acre, 65 lbs/acre, 70 lbs/acre, and 75 lbs/acre. To investigate this research questions, five fields (with differing soil types) at different locations in a Midwestern state are selected for a study. Each field is divided into four plots. For each field, each of the four nitrogen amounts is randomly assigned to one plot each. Each plot is treated with the fertilizer containing the assigned amount of nitrogen. After harvest, the soybean yield (in bu/acre) for each plot is determined. Below are the results of this experiment, with soybean yield reported for each plot. The row and column sample means are also provided. Field
Nitrogen Amount 1 2 3 4 5 Mean
60 lbs/ acre 52.9 45.3 53.0 59.0 44.6 50.96
65 lbs/ acre 43.3 38.5 50.8 53.4 53.2 47.84
70 lbs/ acre 48.8 47.0 53.8 61.6 53.7 52.98
75 lbs/ acre 58.2 53.6 55.0 57.0 56.3 56.02
Mean 50.80 46.10 53.15 57.75 51.95 51.95

Answer the following questions regarding the design of this experiment.
a. What is the treatment factor in this experiment?
b. What are the treatments in this experiment?
c. What is the experimental unit in this experiment?
d. What is the response variable in this experiment?
e. Is randomization implemented in this design? Justify your answer.
f. Is replication implemented in this design? Justify your answer.
g. Is blocking implemented in this design? Justify your answer.