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。
之前买一部手机，大概1000元左右，就可以买一台诺基亚手机。
如今买一部手机，大概10000元左右，可以买一台IPhone Pro
如果来衡量通胀，那么手机的价格上涨了10倍，通胀就是10倍。
所以这种衡量方法，相对于合理值，是偏高的，也就是biased upward。
因为IPhone Pro的体验是诺基亚无法比拟的，虽然都是手机，但是商品的质量发生了巨大的改变。
例子的biased upward是偏高，但是提中biased upward是上调的意思吗？
可以麻烦老师用手机的例子，按题中的条件，讲解一下解题思路吗？
之前买一部手机，大概1000元左右，就可以买一台诺基亚手机。
如今买一部手机，大概还是1000元左右，可以买一台IPhone Pro
