Consider two variable linear regression model: Y = a + Bx+u The following results are given below : EX, = 228, EY; = 3121, EX;Y₁ = 38297, EX² = 3204 and = 3347-60, Ex? = 604-80 and Ey? = 19837 and n = 20 Using this data, estimate a and ß and the variances of your estimates.