A sample of 630 people are asked about the main method of transport used to travel to work. Use the data in the contingency table below, Table 5, to test if there is any association between the main type of transport (bus) for commuting to work and place of residence. Remember to show your method. Table 5: Transport type for commuting to work and residence Transport type Residence Train Bus Private car Total Cities 120 50 30 200 Large towns 90 230 30 350 Rural areas 20 20 40 80 Total 230 300 100 630