13. (HSI) Historical data of closing prices for three stocks and one index in 2005 are shown in table below. Year HSBC HSB Cheung Kong HSI Jul 120 107 80 15 Aug 122 109 78 16 Sept 119 106 76 15 Oct 123 109 79 16 Nov 124 110 81 17 Dec 118 107 80 14 Consider the single factor model: r = a + b +6. Calculate the following quantities: A. the average return on each stock and the index. B. the sample variance of each stock and the index. C. the correlation between the stock and the index. D. b, for each stock E., for each stock. F. the variance of the error for each stock. Check if the single factor model is accurate. (Hint: Apply formulas (5.5) in the locture notes and sample' mean etc)