Two manufacturing processes are available for annealing a certain kind of copper tubing, the primary difference being in the temperature required. The critical response variable is the resulting tensile strength. To compare the methods, fifteen pieces of tubing were broken into pairs. One piece from each pair was randomly selected to be annealed at a moderate temperature, the other piece at a high temperature. The resulting tensile strengths (in tons/sq in.) are listed in the following table. Analyze these data with a Wilcoxon signed rank test. Use a two-sided alternative. Let α = 0.05.

Tensile Strengths (tons/sq in.) Moderate High Pair Temperature Temperature 16.5 17.6 16.9 15.8 18.4 17.5 17.6 16.1 16.8 15.8 16.8 17.3 18.1 17.9 16.4 16.9 17.2 17.0 16.1 18.2 17.7 17.9 16.0 17.3 16.1 16.5 17.6 18.4 17.2 16.5 10 12 13 14 15