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A researcher estimated a model for the daily percentage returns (rt) on the Australian stock market index over the last 100 days of trading and obtained the results: rt=0.15+0.23rt1+0.65log(t2)+utlog(t2)=0.280.06t1ut1+0.91log(t12) The log-likelihood was 829.5. (i) What feature of stock market returns does the mean equation account for? Justify your answer. (1 mark) (ii) Is the conditional variance always positive in this model? Justify your answer. (1 mark) (iii) What feature of stock market returns does the conditional variance equation account for? (1 mark) (iv) Is the news impact curve asymmetric for this model? Justify your answer. (1 mark) A researcher estimated a model for the daily percentage returns (rt) on the Australian stock market index over the last 100 days of trading and obtained the results: rt=0.15+0.23rt1+0.65log(t2)+utlog(t2)=0.280.06t1ut1+0.91log(t12) The log-likelihood was 829.5. (i) What feature of stock market returns does the mean equation account for? Justify your answer. (1 mark) (ii) Is the conditional variance always positive in this model? Justify your answer. (1 mark) (iii) What feature of stock market returns does the conditional variance equation account for? (1 mark) (iv) Is the news impact curve asymmetric for this model? Justify your answer. (1 mark)