4. Tests for Heteroskedasticity 1) Goldfeld-Quandt Test Given a sample with size n (1) Sort it by the order of an independent variable and then portion it into three parts Sub-sample 1 with size n1 Sub-sample 2 with size n2 Sub-sample 3 with size n3 1 tn<n4. Tests for Heteroskedasticity 1) Goldfeld-Quandt Test: Given a sample with size n (1) Sort it by the order of an independent variable and then portion it into three parts. Sub-sample 1 with size n1 Sub-sample 2 with size n2 Sub-sample 3 with size n3 1 3 n n n + 