The Mean Versus the Median: A Case Study in 4-R Act Litigation
通过一起4-R法案诉讼案例，说明法律条文而非数据特性决定了应使用加权均值而非中位数来估算财产税率，强调选择估计量前需明确目标参数。
In a recent case brought under the "4-R Act," the railroads argued that their effective property tax rate should be equalized to the median of the rates for other taxpayers. The language of the statute, however, compels the use of a weighted mean. The choice between the two measures of location is dictated not by their technical properties or by the nature of the data, but by the statute that defines the objectives of the statistical operations. Before choosing an estimator, one has to decide what parameter one is trying to estimate. This principle may seem obvious, but sad experience proves otherwise.