But the agencies argue that their ratings are designed to measure the probabilityof default, not to recommend the purchase of individual securities or to predict market prices.
It's a fine measure, as far as it goes, but it depends critically on both the form of the assumed probability distribution function and the parameters of that distribution.
就目前来说，它是一个好的度量标准，但是这主要取决于假定的概率分布函数的形成和这个函数的参数。
3
According to the dump a, if we were to measure a, we would see "0" or "1" with an equal probabilityof 0.5 (0.707107 2).