A hypothesis test, based on a paired sample, is to be performed to compare the means of

Question:

A hypothesis test, based on a paired sample, is to be performed to compare the means of two populations. The sample of 15 paired differences contains an outlier but otherwise is approximately bell shaped. Assuming that removal of the outlier would not be legitimate, would use of the paired t-test or a nonparametric test be better? Explain your answer.