Return to the data for Exercise 9 in Chapter 6, with the data in Table 6.26. (a) Is there evidence that any of these particular four suppliers have a different distribution for the tensile strength of...

Return to the data for Exercise 9 in Chapter 6, with the data in Table 6.26.

(a) Is there evidence that any of these particular four suppliers have a different distribution for the tensile strength of the material?

(b) Use pairwise comparisons to say which suppliers tend to have the greater tensile strength.

Exercise 9

A manufacturer of air conditioning ducts is concerned about the variability of the tensile strength of the sheet metal among the many suppliers of this material.

Four samples of sheet metal from four randomly chosen suppliers are tested for tensile strength. The data are given in Table 6.26.

(a) Perform the appropriate analysis to ascertain whether there is excessive variation among suppliers.

(b) Estimate the appropriate variance components.