## Description

1. Twelve orange pulp silage samples were divided at random into four

groups of three. One group was left as an untreated control while

the other three groups were treated with formic acid, beet pulp, and

sodium chloride, respectively.

The observed moisture content of the

silage samples are shown below.

Sodium chloride Formic acid Beet pulp Control

80.5 89.1 77.8 76.7

79.3 75.7 79.5 77.2

79.0 81.2 77.0 78.6

(a) Obtain an analysis of variance table for the data and test the null

hypothesis that all four treatments yield the same true average

moisture content. Use α = 0.05.

(b) Compute a 99% confidence interval for the difference in response

between the average of the three treatment groups (acid, pulp,

and salt) and the control group.

(c) Compute 95% simultaneous confidence intervals for the differences

in response between each of the three treatment groups versus the

control group. Use the method among Bonferroni, Tukey, and

Scheff´e, that give the shortest intervals.

2. In an experiment with five treatment groups and 25 residual degrees of

freedom, for what numbers of contrasts is the Bonferroni method more

powerful than the Scheff´e method?