Problem 1

Clothing manufacturers use a wear-testing machine to measure different fabrics’ ability to withstand abrasion. The wear of the material is measured by weighing the clothing after it has been through the wear-testing machine. A manufacturer wants to determine if there is a difference between the average weight loss among four different materials. The experiment is done by using four samples of each kind of material. The samples were tested in a completely randomized order. The weights are listed below. Use the data below and a 1% significance level to construct an ANOVA table and to determine if at least one fabric is significantly different from the others.

           Fabric
   A        B      C      D
1.93 2.55 2.40 2.33
2.38 2.72 2.68 2.40
2.20 2.75 2.31 2.28
2.25 2.70 2.28 2.25