Resumen de Speaking Stata: Trimming to taste

Nicholas J. Cox

• Trimmed means are means calculated after setting aside zero or more values in each tail of a sample distribution. Here we focus on trimming equal numbers in each tail. Such trimmed means define a family or function with mean and median as extreme members and are attractive as simple and easily understood summaries of the general level (location, central tendency) of a variable. This article provides a tutorial review of trimmed means, emphasizing the scope for trimming to varying degrees in describing and exploring data. Detailed remarks are included on the idea�s history, plotting of results, and confidence interval procedures. Examples are given using astronomical and medical data. The new Stata commands trimmean and trimplot are also included.