In Ecological Engineering (Feb. 2004), a new methodology for tree seedling production (called aqua-forest system) was compared to a conventional tree nursery method. The new method was applied to four plants grown in a clean-water creek (Treatment T1) and four plants grown in a polluted water creek (Treatment T2), while the conventional method (Treatment T3) was applied to four plants raised in a tree nursery. Thus, the experimental design was completely randomized with three treatments and four replicates (plants) per treatment. One dependent variable of interest was the ratio of shoot weight to root weight. Tukey’s multiple comparisons of the three treatment means yielded the following results at an experiment wise error rate of .05:

a. How many pairwise comparisons are made in the Tukey analysis?

b. Which treatment(s) yielded the significantly highest mean shoot/root ratio? The lowest?

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Mean Shoot/ 1.50 2.31 3.29 Root Ratio: Treatment: T1 T2 T3