could you explain each question to me? thank you!

1. (20pts, each 5pts) Explain why the following statements are true or false (a) 211:1( 102 > 211:1 (Y:- 102 where - is the tted value of the dependent variable Y; from the OLS regression and l7 is the sample mean of K. (b) Gauss-Markov theorem states that OLS has the smallest standard errors among all linear and unbiased estimators. (c) For two random variables X and Y suppose Cm:[X,Y] = 1. Then Var[X + Y]