同样的问题，解法不一样。

NO.PZ2023101902000037 问题如下 analyst reports the following funinformation to the aisor of a pension funthcurrently invests in government ancorporate bon ancarries a surplus of US10 million.To evaluate the sufficienof the funs surplus, the aisor estimates the possible surplus values the enof one year. The aisor assumes thannureturns on assets anthe annugrowth of the liabilities are jointly normally stributeantheir correlation coefficient is 0.8. The aisor creport that, with a confinlevel of 95%, the surplus value will greater thor equto: A.US-11.4 million B.US-8.3 million C.US-1.7 million US0 million The lower bounof the 95% confinintervis equto: ExpecteSurplus – (95% confinfactor × Volatility of Surplus). The requirevariables ccalculatefollows: Varianof the surplus = 1002 × 10%2 + 902 × 5%2 – 2 × 100 × 90 × 10% × 5% × 0.8 = 48.25 Volatility of the surplus = 6.94 The expectesurplus = 9.7 Therefore, the lower bounof the 95% confininterv= 9.7 – 1.645 × 6.94 = -1.725 VaR_asst= 100*(-0.06+1.645*0.1)VaR_l= 90*(-0.07+1.645*0.05)95% surplus risk = sqrt(VaR_asst^2+VaR_l^2- 2*VaR_l*VaR_asst*0.8)如果可以，算出来结果是-1.3

NO.PZ2023101902000037 问题如下 analyst reports the following funinformation to the aisor of a pension funthcurrently invests in government ancorporate bon ancarries a surplus of US10 million.To evaluate the sufficienof the funs surplus, the aisor estimates the possible surplus values the enof one year. The aisor assumes thannureturns on assets anthe annugrowth of the liabilities are jointly normally stributeantheir correlation coefficient is 0.8. The aisor creport that, with a confinlevel of 95%, the surplus value will greater thor equto: A.US-11.4 million B.US-8.3 million C.US-1.7 million US0 million The lower bounof the 95% confinintervis equto: ExpecteSurplus – (95% confinfactor × Volatility of Surplus). The requirevariables ccalculatefollows: Varianof the surplus = 1002 × 10%2 + 902 × 5%2 – 2 × 100 × 90 × 10% × 5% × 0.8 = 48.25 Volatility of the surplus = 6.94 The expectesurplus = 9.7 Therefore, the lower bounof the 95% confininterv= 9.7 – 1.645 × 6.94 = -1.725 如题，不是要用权重来求的吗 100/(100+90），请问这个该怎么理解

NO.PZ2023101902000037问题如下 analyst reports the following funinformation to the aisor of a pension funthcurrently invests in government ancorporate bon ancarries a surplus of US10 million.To evaluate the sufficienof the funs surplus, the aisor estimates the possible surplus values the enof one year. The aisor assumes thannureturns on assets anthe annugrowth of the liabilities are jointly normally stributeantheir correlation coefficient is 0.8. The aisor creport that, with a confinlevel of 95%, the surplus value will greater thor equto: A.US-11.4 millionB.US-8.3 millionC.US-1.7 millionUS0 millionThe lower bounof the 95% confinintervis equto: ExpecteSurplus – (95% confinfactor × Volatility of Surplus). The requirevariables ccalculatefollows: Varianof the surplus = 1002 × 10%2 + 902 × 5%2 – 2 × 100 × 90 × 10% × 5% × 0.8 = 48.25 Volatility of the surplus = 6.94 The expectesurplus = 9.7 Therefore, the lower bounof the 95% confininterv= 9.7 – 1.645 × 6.94 = -1.725上一题的surplus risk跟这题的surplus value是不一样的对吗surplus risk用的是expectesurplus growth（增量)去计算，surplus value用的是expectesurplus？这样理解对吗

NO.PZ2023101902000037问题如下 analyst reports the following funinformation to the aisor of a pension funthcurrently invests in government ancorporate bon ancarries a surplus of US10 million.To evaluate the sufficienof the funs surplus, the aisor estimates the possible surplus values the enof one year. The aisor assumes thannureturns on assets anthe annugrowth of the liabilities are jointly normally stributeantheir correlation coefficient is 0.8. The aisor creport that, with a confinlevel of 95%, the surplus value will greater thor equto: A.US-11.4 millionB.US-8.3 millionC.US-1.7 millionUS0 millionThe lower bounof the 95% confinintervis equto: ExpecteSurplus – (95% confinfactor × Volatility of Surplus). The requirevariables ccalculatefollows: Varianof the surplus = 1002 × 10%2 + 902 × 5%2 – 2 × 100 × 90 × 10% × 5% × 0.8 = 48.25 Volatility of the surplus = 6.94 The expectesurplus = 9.7 Therefore, the lower bounof the 95% confininterv= 9.7 – 1.645 × 6.94 = -1.725​expectesurplus不应该是100✘6%-7%✘90吗