A Study of Robust Estimators

Using the compiled analytical data for the constituents of four Canadian iron-formation reference samples, a comparison is made among nine different "robust" estimators of "true" value, including the median, median, Gastwirth median, trimean, quarter-trimmed and sixthtrimmed means and the three Hampel estimators. Individual estimators and combinations of them are compared by means of the summation and "iron-oxide compatibility" tests. Comparisons are also made with values derived by the "select laboratories" method.