The model is a chai square test of independence. How many degrees of freedom does this test have?

Question 1 to 5 500 high school students were classified by level of stress and school district location. The contingency table is shown below Can you support the claim that there is a difference in level of stress due to type of school district? Medium High Stress Low Stress Total Stress Urban District 50 100 50 200 Suburban 125 90 35 250 District Rural District 15 10 25 50 Total 190 200 110 500