In the article “The effect of hydrogel and solution of sodium ascorbate on the bond strength of bleached enamel” published in the Journal of Conservative Dentistry

(Paul et al., 2007), the authors reported the results of an experiment studying the effects of four different bleaching treatments on the enamel surfaces of maxillary molars. Each of the four treatments was replicated 10 times and Table 12.31 contains summary statistics reported in the article and the ANOV table given in Table 12.32 was reconstructed from the information in Table 12.31. Use Table 12.31 and 12.32 to answer the following:

(a) On the basis of the information in Table 12.31, is it reasonable to assume the treatment groups have a common variance? Explain.

(b) Test the hypothesis of equal treatment means at the ???? = 0.05 level.

(c) Determine the Bonferroni distance ???? for separating the treatment means when the experimentwise error rate is ????E = 0.05.

(d) Separate the treatment means and summarize the separation of the treatment means using the underline notation.

(e) Compute a 95% confidence interval for the difference between the means of the no-sodium ascorbate treatment and the 20% sodium ascorbate hydrogel treatment.

(f) Compute a 95% confidence interval for the mean of the 20% sodium ascorbate hydrogel treatment.