QUESTION 10 Which one of the following is not an assumption of the neoclassical simple linear regression (NSR) model applied to a situation in which we wish to estimate a conditional expectation function E(Y] X) based on a sample consisting of 'n' paired observations {(X1,Y1), (X2,Y2) (Xn,Yn)}? 0 Random disturbances associated with any two observations have a zero covariance conditional on the sample values for X. 0 The random variables (X1,X2 ..... X\") are multivariate normally distributed. 0 There is variation in the values taken by X in the observed sample. 0 For each observation the variance of the random disturbance conditional on the sample values for X is the same