The effect of plant growth regulators and spear bud scales on spear elongation in asparagus was investigated by Yang-Gyu and Woolley (2006). Elongation rate of spears is an important factor determining final yield of asparagus in many temperate climatic conditions. Spears were harvested from 6-year-old Jersey Giant asparagus plants grown in a commercial planting at Bulls (latitude 40.2S, longitude 175.4E), New Zealand. Spears were harvested randomly and transported from field to lab for investigation. After trimming to 80mm length, spears were immersed completely for 1 h in aqueous solutions of 10 mg l-1 concentration of indole- 3-acetic acid (IAA), abscisic acid (ABA), GA3, or CPPU (Sitofex EC 2.0%; SKW, Trostberg, Germany) in test tubes. Control spears were submerged in distilled water for 1 h. The experiment was a completely randomized design with five replications (spears) per treatment. The resulting data (final spear length in mm) is shown in the table below. Control IAA ABA GA3 CPPU 94.7 89.9 96.8 99.1 104.4 96.1 94.0 87.8 95.3 98.9 86.5 99.1 89.1 94.6 98.9 98.5 92.8 91.1 93.1 106.5 94.9 99.4 89.4 95.7 104.8

(a) Perform the analysis of variance to test the hypothesis of no treatment effect. (b) Define 1 be the mean response for the Control group, and 2,3,4,5 be the that for the other groups, respectively. Define = 1 (2+3+4+5)/4 . Use a t-test to test H0 : = 0 vs HA : = 0, and give a 95% confidence interval of . (c) Use the Tukey's HSD method to test all pairwise comparisons of treatment means.