7 Regression Equation Y =   x 1 +   x 2...+  p x p + v X k = x k + u k Observable Variables b = S XX -1 S XY does not converge to  b* := (S XX -  uu ) -1 S XY In multiple regression Examples with EQS of regression with error in variables Using suplementary information to assessing the magnitude of variances of errors in variables.