Test of parameters This variance-covariance matrix can be used to test whether a parameter or a group of parameters is equal to zero. vla var(b) No,)b, [var(b)]b, x(#ofb, Finally, the test of overidentifying restriction is a test of the overall fit of the model TU=I min[gr(b)'58(6)]-x(of moments-#of parameters {b}Test of parameters • This variance-covariance matrix can be used to test whether a parameter or a group of parameters is equal to zero, via • Finally, the test of overidentifying restriction is a test of the overall fit of the model, ~ ( 0,1) ) ˆ var( ˆ N b b ii i ~ (# ) ˆ ) ] ˆ [var( ˆ 1 2 b j b jj b j χ ofb j − { } [ ( )' ( )] ~ (# # ) 1 2 TJ T min g b S g b of moments of parameters T T b T = − − χ