11.27 The article “A Shovel with a Perforated Blade Reduces Energy Expenditure Required for Digging Wet Clay”

(Human Factors, 2010: 492–502) reported on a study in which each of 13 workers was provided with both a conventional shovel and a shovel whose blade was perforated with small holes. The authors of the cited article provided the following data on energy expenditure

[(kcal/kg(subject)/lb(clay]:

Worker: 1 2 3 4 5 6 7 Conventional: .0011 .0014 .0018 .0022 .0010 .0016 .0028 Perforated: .0011 .0010 .0019 .0013 .0011 .0017 .0024 Worker: 8 9 10 11 12 13 Conventional: .0020 .0015 .0014 .0023 .0017 .0020 Perforated: .0020 .0013 .0013 .0017 .0015 .0013 Do these data provide convincing evidence that the mean energy expenditure using the conventional shovel exceeds that using the perforated shovel? Test the relevant hypotheses using a significance level of 0.05.