1. Application of Linear Regression (a) State the population relationship assumed to hold in a multiple iinear regression (MLR) model with two regressoi's, I] and 1:2 and dependent variable 3*. (Allow 3:1 and 1:2 to enter linearlyno logs, no squares, etc.) (b) State the difference between the population regression line and the tted regression line. (c) Under what four assumptions does this multiple linear regression (MLR) produce an unbiased estimate of coefcient Ba and [91? Expiain them both mathematically and in words. (d) 1What does \"Best\" mean in the term Best Linear Unbiased Estimates (BLUE)? Compared with l (c), which additional assumption do we need to obtain the BLUE? Explain it both mathematically and in words. (e) 1ilrhich assumption do we need to do the inference? Which theorem justies this assumption and why can this theorem justies it