9. Do not use computer. Five observations of two variables are given as follows. X Y -2 -7.1 -1 -4.0 0 1 2 -2.1 1.6 4.3 Consider a linear regression model when Y is regressed on X. It is given that 1 1 d [a b] = ad = bc c -7] a) Calculate the least squares estimates of the intercept and the slope. b) Calculate the standard errors of the estimated intercept and slope. c) Construct a 95% confidence interval for each parameter. d) Test at the 5% level of significance whether the slope is 3. Estimate the mean of Y when X = -1.5. Construct a 95% confidence interval for the estimate.