NO.PZ2017100901000025
问题如下：
A product is part of a price index based on a fixed consumption basket. If, over time, the product’s quality improves while its price stays constant, the measured inflation rate is most likely:
选项：
A. unaffected.
B. biased upward.
C. biased downward.
解释：
B is correct.
As the quality of a product improves, it satisfies people’s needs and wants better. The measured inflation rate is skewed higher than otherwise unless an adjustment is made for the increase in the quality of the good. Even if the good’s price had increased over time, the improvements in quality would still bias the measured inflation rate upward.
考点： inflation Measurement
解析：更好质量的产品应该对应更高的价格水平，现在物价水平没有变动，但是质量变好了。
那么经过审慎思考的通胀率( measured inflation rate )就应该上调当前通胀率的数值，以此来反应商品质量的进步。
调整过的index那不就是正确的了么？为何还会有bias偏误呢？是说调整后的跟没调整的真实数据比么？
