K²=n(ad-bc)²/(a+b)(c+d)(a+c)(b+d) (其中n=a+b+c+d)P(K²>=k0) 0.50 0.40 0.25 0.15 0.10 0.05 0.025 0.010 0.005 0.001 k0 0.455 0.708 1.323 2.702 2.706 3.841 5.024 6.635 7.879 10.828