Statistical Artifacts in the Ratio of Discrete Quantities

The ratio is a familiar statistic, but it is often misused. One frequently overlooked problem occurs when ratioing two discrete (digitized) variables. Fine structure appears in the histogram of the ratio that can be very subtle, or can sometimes even dominate the histogram. It disappears when the numerator and/or denominator become continuous. This statistical artifact is not a binning error, nor is it removed by taking more data. It is important to be aware of the artifact in order to avoid misinterpretation of ratio data. We provide examples of the statistical artifact (including one from baseball) and discuss ways to avoid or minimize the problems it can cause.     

青铜文物保护研究现状及发展趋势

介绍了青铜文物保护的研究现状 ,对已有的青铜文物保护技术进行了分析比较 ,指出其优缺点 ,重点介绍了BTA和AMT两种缓蚀剂 ,并且指出青铜文物保护研究面临的问题及发展趋势。