稍微较个真， 贝塔数学角度理解就是因变量相对于某个自变量单位变化的变动，按道理不管咋弄因变量还是那个熟悉，贝塔不会变呀

NO.PZ2019052801000026问题如下 Suppose we have a well-versifie$100 million equity portfolio. The portfolio beta relative to the S P 500 is 1.2. The current value of the 3-month S P 500 Inx is 1,000. The multiplier is 250. If we want to aust the portfolio beta to 1.8, how many S P 500 contracts we neeA.long 200 contracts.B.long 220 contracts.C.long 280 contracts.long 240 contracts.is correct.考点Heing With StoInx Futures解析(1.8−1.2)100,000,001,000×250=0.6×400=240(1.8-1.2)\frac{100,000,00}{1,000\times250}=0.6\times400=240(1.8−1.2)1,000×250100,000,00​=0.6×400=240where beta = 1.2, target beta = 1.8, A = 250 x 1,000, P = $100 million还是long或者short这个方向搞不懂。如果我先计算beta1.2的时候，需要short480份，再计算beta01.2，需要short720份，从-480到-720，不是应该short160吗？老师我这个算法和思路是错误的吗？

NO.PZ2019052801000026 问题如下 Suppose we have a well-versifie$100 million equity portfolio. The portfolio beta relative to the S P 500 is 1.2. The current value of the 3-month S P 500 Inx is 1,000. The multiplier is 250. If we want to aust the portfolio beta to 1.8, how many S P 500 contracts we nee A.long 200 contracts. B.long 220 contracts. C.long 280 contracts. long 240 contracts. is correct.考点Heing With StoInx Futures解析(1.8−1.2)100,000,001,000×250=0.6×400=240(1.8-1.2)\frac{100,000,00}{1,000\times250}=0.6\times400=240(1.8−1.2)1,000×250100,000,00​=0.6×400=240where beta = 1.2, target beta = 1.8, A = 250 x 1,000, P = $100 million we have a well-versifie$100 million equity portfolio. 担心股票下跌对吗？ 担心——发生收益的hee，是这样吗？为什么不是short 240, 而是long呢？

NO.PZ2019052801000026 long 220 contracts. long 280 contracts. long 240 contracts. is correct. 考点Heing With StoInx Futures 解析 (1.8−1.2)100,000,001,000×250=0.6×400=240(1.8-1.2)\frac{100,000,00}{1,000\times250}=0.6\times400=240(1.8−1.2)1,000×250100,000,00​=0.6×400=240 where beta = 1.2, target beta = 1.8, A = 250 x 1,000, P = $100 million 这个就是1.8—1.2。全面一道题是1.1—0.75 什么情况下beta在前面。什么情况下要在计算时就把负号加进去

答案看不见，新系统不兼容吗？