问题如下：
The beta of a security estimated from historical returns is equal to the true beta of the security. True or false? Discuss.
解释：
This statement is false. The beta of a security obtained from past data is only an estimate of the true beta, which is unknown. The estimate is subject to statistical estimation errors and the true beta, at best, can be said to fall within a confidence interval with a given probability (the confidence level).
