Perform the analysis of variance at the 0.05 level of significance and indicate whether or not the mean tensile strengths differ significantly for the six machines.

13.1 Six different machines are being considered for use in manufacturing rubber seals. The machines are being compared with respect to tensile strength of the product. A random sample of four seals from each ma chine is used to determine whether the mean tensile strength varies from machine to machine. The follow ing are the tensile-strength measurements in kilograms per square centimeter X 101: Machine 1 2 3 4 5 6 17.5 16.4 20.3 14.6 17.5 18.3 16.9 19.2 15.7 16.7 19.2 16.2 15.8 17.7 17.8 20.8 16.5 17.5 18.6 15.4 18.9 18.9 20.5 20.1