The disturbance term under the Classical Assumptions is assumed to be . normally distributed with constant, non-zero mean and zero variance normally distributed with zero mean and varying variance normally distributed with varying mean and zero variance normally distributed with zero mean and constant variance 5 2 points Under autocorrelation, if the standard error of B1 for OLS is negatively biased, then the t-statistic is O has unknown bias positively biased unaffected O negatively biased