The article "A Shovel with a Perforated Blade Reduces Energy Expenditure Required for Digging Wet Clay" (Human Factors, 2010: 492-502) described a study in which each of 13 workers performed a task using a conventional shovel and using a shovel whose blade was perforated with small holes. The authors of the cited article provided the following data on energy expenditure (in Kcal/ kg( subject)/lb( clay):

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.

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Worker: Conventional: 0.0011 0.0014 0.0018 0.0022 0.0010 0.0016 0.0028 Perforated 0.0011 0.0010 0.0019 0.0013 0.0011 0.0017 0.0024 6 Worker: Conventional: 0.0020 0.0015 0.0014 0.0023 00017 0.0020 Perforated: 0.0020 0.0013 0.0013 0.0017 0.0015 0.0013 9 10 13