An estimator On of some unknown population parameter 0, based on sample size n, is unbiased if Select one: Oa. On =0 Vn Ob. E(On) =0 Vn O c. var(On) =0 Vn UA e =(")H POThe next graph shows the pdfs of two estimators (1, 02) of unknow population parameter 0. PDF of estimator 0.4 Estimators: 0.3 Density -2 2 4 5 6 7 8 X Suppose that the true value of the unknown parameter is 0 = 3. Select one: Oa. Both estimators , and 02 are unbiased. O b. Estimator 2 is unbiased, and 01 is biased. O C. Both estimators @1 and 02 are biased. O d. Estimator @1 is unbiased, and 02 is biased .Suppose that you are estimating the simple regression model Y, = B1 + 82 X; + u;, and in your sample, the dependent variable and regressor are positively correlated. Select one: O a. The OLS estimator of the slope, by > 0. O b. The OLS estimator of the slope, by 0. O d. The sign of the OLS slope estimator depends of the variance of X and Y in the sample.Suppose you are estimating the unknown population mean /, using the sample average as your estimator: Xn = 1 EtXi What is the variance of your estimator? That is, find var( An ), denoting the population variance with o2 Select one: O a. Ob. 0 Oc. 02 O d.Suppose that X is a random variable with mean pix and standard deviation ox. What is the mean (expected value) of Z = X-HX 7 Select one: O a. E(Z) = 0 O b. Depends on the values of Ax , Ox O c. E(X) O d. E(Z) = 1