Can someone help with these questions?

3. Regression Theory: The OLS estimator for the slope in a bi-variate re- gression can be written. 3 = 2(i-x)(yi-y) . Assuming the 4 assumptions of the simple linear regression model, show that the OLS estimator is unbiased, i.e. that E[B] = B. The four assumptions are: . SLR.1: Linear in paramters. y = Bo + Bix tu . SLR.2: random sampling . SLR.3: sample variation in the xi . SLR.4: E(ux) = 0 . In addition, assume that the xi's are fixed in repeated samples