(a) Using \(q_{0.10}=3.921\) for the Tukey HSD method, compare the strength of the 5 linen threads in Exercise 12.23 .

(b) Use the Bonferroni confidence interval approach on page 411, with \(\alpha=0.10\), to compare the mean linen thread strengths in Exercise 12.20.

Data From Exercise 12.23

Data From Exercise 12.20

Data From Example 7

Data From Example 6

12.23 A laboratory technician measures the breaking strength of each of 5 kinds of linen thread by means of 4 different instruments and obtains the following results (in ounces): Measuring Instrument 11 12 13 14 Thread 1 20.6 20.7 20.0 21.4 Thread 2 24.7 26.5 27.1 24.3 Thread 3 25.2 23.4 21.6 23.9 Thread 4 24.5 21.5 23.6 25.2 Thread 5 19.3 21.5 22.2 20.6 Looking at the threads as treatments and the instru- ments as blocks, perform an analysis of variance at the level of significance = 0.01.