A hypothesis test based on a simple random paired sample is to be performed to compare the

Question:

A hypothesis test based on a simple random 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 removing the outlier is not legitimate, which test is better to use-the paired t-test or the paired Wilcoxon signed-rank test? Explain your answer.