20%截尾均值计算

How to Find a Trimmed Mean

Example: Find the trimmed 20% mean for the following test scores: 60, 81, 83, 91, 99.

Step 1: Trim the top and bottom 20% from the data. That leaves us with the middle three values:
60, 81, 83, 91, 99.

Step 2: Find the mean with the remaining values. The mean is (81 + 83 + 91) / 3 ) = 85.

Warning: This is one of those challenging terms that seem to have different meanings to different authors. Perform a Google search for trimmed mean and you’ll find some authors who state a trimmed mean of 10% is where a TOTAL of 10% of data points is removed (i.e. 5% from either side) as opposed to trimming 10% from each side. Your teacher/professor/boss will likely use the term exactly as it’s stated in this article, but you may want to clarify before you actually do any calculations.

Sources:
SUNY Oswego
University of Minnesota
UCLA

注意，如果是使用软件来计算截尾均值，那么Excel和SPSS的算法略有不同，自己需要注意这点。

转载自：http://www.statisticshowto.com/trimmed-mean/