Exercises for Section 9.2
1. The article “Organic Recycling for Soil Quality Conservation in a Sub-Tropical Plateau Region” (K. Chakrabarti, B. Sarkar, et al., J. Agronomy and Crop Science. 2000:137–142) reports an experiment in which soil specimens were treated with six different treatments, with two replicates per treatment, and the acid phosphate activity (in μmol p-nitrophenol released per gram of oven-dry soil per hour) was recorded. An ANOVA table for a one-way ANOVA follows.
The treatment means were
- a. Can you conclude that there are differences in acid phosphate activity among the treatments?
- b. Use the Tukey–Kramer method to determine which pairs of treatment means, if any. are different at the 5% level.
- c. Use the Bonferroni method to determine which pairs of treatment means, if any, are different at the 5% level.
- d. Which method is more powerful in this case, the Tukey–Kramer method or the Bonferroni method?
- e. The experimenter notices that treatment A had the smallest sample
mean , while treatment B had the largest. Of the Fisher LSD method, the Bonferroni method, and the Tukey-Kramer method, which, if any, can be used to test the hypothesis that these two treatment means are equal?
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