Futures price is the unbiased estimate of expected spot price, which is based on the function of risk transferring. 期货价格是未来现货价格的无偏估计,这是建立在风险转移功能基础之上的。
Unbiased estimators are not necessarily consistent, but those whose variances shrink to zero as the sample size grows are consistent. 无偏估计量未必是一致的,但是那些当样本容量增大时方差会收缩到零的无偏估计量是一致的。