In this study the later might have been appropriate, although, I can not say whether the assumptions are fulfilled or not. But still the term paired would complicate the matter. Thirdly, the study tried to shown that this data was not normal, and for that reason non-parametric tests were applied. In conclusion, I would like to address that cautions be made in analysis for any statistical inference. The role of statistics in survey research is very important, but it is equally important for that role to be seen in its proper perspective.
Empirical research is first and foremost a logical, rather than a mathematical operation.
Mathematics is merely a convenient and efficient language for describing the logical operations inherent in good data analysis. W.B. Saunders company. Philadelphia, Pennsylvania 2. Wadsworth Publishing Company, Belmont, California. Survey research methods by Earl Babbie 2nd ed.