There exist many misconceptions in choosing the t over the Wilcoxon Rank-Sum test when testing for shift. Examples are given in the following three groups: (1) false statement, (2) true premise, but false conclusion, and (3) true statement irrelevant in choosing between the t test and the Wilcoxon Rank Sum test.
Sawilowsky, Shlomo S.
"Misconceptions Leading to Choosing the t Test Over the Wilcoxon Mann-Whitney Test for Shift in Location Parameter,"
Journal of Modern Applied Statistical Methods:
2, Article 26.
Available at: http://digitalcommons.wayne.edu/jmasm/vol4/iss2/26