3. We have 6 assumptions for our OLS regressions: (i) the Population Model; (ii) Random Sampling; (iii) No Perfect Collinearity (iv) Mean Independence; (v) homoskedasticity; and (vi) Normally distributed errors. (a) Formally write out our mean-independence assumption for the disturbance u over the explanatory variables (21, ..., Jk) (b) What is the minimal set of the above assumptions that we require in order to show that our slope coefficients are unbiased? (c) Which assumptions do we need in order to conduct inference using classical t and F tests if we have a small sample? (d) If we have a very large sample, which of the above assumptions are necessary for asymptotic t and F tests