An experiment was made to measure the mean number of axe strikes that is necessary to cut a tree trunk. 16 identical tree trunks were cut by a randomly chosen person. Observation Number of strikes 2 3 4 5 6 7 8 9 10 12 13 14 15 16 52.43 54.9 49.1 45.72 44.97 47.58 53.9 45.45 46.01 48.55 55.73 43.34 41.07 54.8 46.59 52.36 Use the Wilcoxon signed-rank test to investigate the claim that the median number of strikes is 50. Use a = 0.05. Assume that the alternative is two-sided.