One of the authors travels regularly to Seattle, Washington. He uses either Delta or Alaska. Flight delays

Question:

One of the authors travels regularly to Seattle, Washington. He uses either Delta or Alaska. Flight delays are sometimes unavoidable, but he would be willing to give most of his business to the airline with the best on-time arrival record. The number of minutes that his flight arrived late for the last six trips on each airline follows. Is there evidence that either airline has superior on-time arrival performance? Use a = 0.01 and the Wilcox on rank-sumtest.