12. A manufacturer of paper used for making grocery bags is interested in improving the tensile strength of the product. A product engineer thinks that tensile strength is a function of the hardwood concentration in the pulp and that the range of hardwood concentrations of practical interest is between 5 and 20%. A team of engineers responsible for the study decides to investigate four levels of hardwood concentration. 5%,10%,15% and 20%. They decide to make up six test specimens at each concentration level, using a pilot plant. All 24 specimens are tested on laboratory tensile tester, in random order. The data from this experiment are shown in the table. Construct ANOVA table to determine whether hardwood concentration is a significant factor or not at =0.05