A transportation strategist wanted to compare the traffic congestion levels across four continents: Asia, Europe, North America, and South America. The file Congestion Level contains congestion level, defined as the increase (%) in overall travel time when compared to a free flow situation (an uncongested situation) for 10 cities in each continent. Required:
At the 0.05 level of significance, is there evidence of a difference in the median congestion levels across continents?