basis的定义到底是什么？

NO.PZ201601050100001707 问题如下 Whiof Whitacre’s two statements regarng bonfutures arbitrage is correct? A.Only Statement 4 B.Only Statement 5 C.Both Statement 4 anStatement 5 A is correct. If the basis is positive, a trar woulmake a profit “selling the basis”—this, selling the bonanbuying the futures. In contrast, when the basis is negative, the trar woulmake a profit “buying the basis,” in whithe trar woulpurchase the bonanshort the futures. B is incorrebecause Statement 5 is incorrect. If the basis is negative, a trar woulmake a profit “buying the basis”—this, purchasing (not selling) the bonanshorting (not buying) the futures. C is incorrebecause Statement 5 is incorrect. If the basis is negative, a trar woulmake a profit “buying the basis”—this, purchasing (not selling) the bonanshorting (not buying) the futures. 中文解析如果basis为正，则应该sell the basis，具体来说就是卖出债券，买入债券期货合约。如果basis 为负，则应该buy the basis，具体来说就是买入债券，卖出对应的债券期货合约。因此只有表述4是正确的，选择 请问这道题对应的是哪页讲义？

NO.PZ201601050100001707 问题如下 Whiof Whitacre’s two statements regarng bonfutures arbitrage is correct? A.Only Statement 4 B.Only Statement 5 C.Both Statement 4 anStatement 5 A is correct. If the basis is positive, a trar woulmake a profit “selling the basis”—this, selling the bonanbuying the futures. In contrast, when the basis is negative, the trar woulmake a profit “buying the basis,” in whithe trar woulpurchase the bonanshort the futures. B is incorrebecause Statement 5 is incorrect. If the basis is negative, a trar woulmake a profit “buying the basis”—this, purchasing (not selling) the bonanshorting (not buying) the futures. C is incorrebecause Statement 5 is incorrect. If the basis is negative, a trar woulmake a profit “buying the basis”—this, purchasing (not selling) the bonanshorting (not buying) the futures. 中文解析如果basis为正，则应该sell the basis，具体来说就是卖出债券，买入债券期货合约。如果basis 为负，则应该buy the basis，具体来说就是买入债券，卖出对应的债券期货合约。因此只有表述4是正确的，选择 何老师在基础班课题讲ily roll这块时专门提到Basis是F-S, 但是这里又明明指S-F,信息冲突了

NO.PZ201601050100001707 问题如下 Whiof Whitacre’s two statements regarng bonfutures arbitrage is correct? A.Only Statement 4 B.Only Statement 5 C.Both Statement 4 anStatement 5 A is correct. If the basis is positive, a trar woulmake a profit “selling the basis”—this, selling the bonanbuying the futures. In contrast, when the basis is negative, the trar woulmake a profit “buying the basis,” in whithe trar woulpurchase the bonanshort the futures. B is incorrebecause Statement 5 is incorrect. If the basis is negative, a trar woulmake a profit “buying the basis”—this, purchasing (not selling) the bonanshorting (not buying) the futures. C is incorrebecause Statement 5 is incorrect. If the basis is negative, a trar woulmake a profit “buying the basis”—this, purchasing (not selling) the bonanshorting (not buying) the futures. 中文解析如果basis为正，则应该sell the basis，具体来说就是卖出债券，买入债券期货合约。如果basis 为负，则应该buy the basis，具体来说就是买入债券，卖出对应的债券期货合约。因此只有表述4是正确的，选择 2. 所以当basis为负数的时候，就是现货高于期货价格，买低卖高的原则下，我们应该买现货卖期货；同理如果basis为正数，应该买期货卖现货了。3. 然后注意basis为负的时候的操作叫做buying basis；basis为正的时候的操作叫做sell basis。现货价格高于期货价格，买低卖高不应该是买期货卖现货吗？下面这个为什么basis为负，叫做buy，buy 的主体是哪一方？

NO.PZ201601050100001707 问题如下 Whiof Whitacre’s two statements regarng bonfutures arbitrage is correct? A.Only Statement 4 B.Only Statement 5 C.Both Statement 4 anStatement 5 A is correct. If the basis is positive, a trar woulmake a profit “selling the basis”—this, selling the bonanbuying the futures. In contrast, when the basis is negative, the trar woulmake a profit “buying the basis,” in whithe trar woulpurchase the bonanshort the futures. B is incorrebecause Statement 5 is incorrect. If the basis is negative, a trar woulmake a profit “buying the basis”—this, purchasing (not selling) the bonanshorting (not buying) the futures. C is incorrebecause Statement 5 is incorrect. If the basis is negative, a trar woulmake a profit “buying the basis”—this, purchasing (not selling) the bonanshorting (not buying) the futures. 中文解析如果basis为正，则应该sell the basis，具体来说就是卖出债券，买入债券期货合约。如果basis 为负，则应该buy the basis，具体来说就是买入债券，卖出对应的债券期货合约。因此只有表述4是正确的，选择 当basis为负数的时候，就是现货高于期货价格，买低卖高的原则下，我们应该买现货卖期货；同理如果basis为正数，应该买期货卖现货了。这个理解但是期货为啥当basis为负数的时候是buy 呢？ basis 的横坐标和纵坐标是啥呢？