In fact, statistics on past stock market performance mislead because of what statisticians call “selection bias,” which occurs when the sample from which a statistic is derived is not representative of all the data. Several kinds of selection bias must be considered when we look at Siegel’s constant.
事实上，由于统计家们所谓的“选择偏误”，即当采取数据的样本无法代表所有数据，以往的股票市场行为的数据有误导之嫌 。当我们看Siegel衡量的时候，我们必须把几种选择偏误列入考虑。