The bimean: A measure of central tendency that accommodates outliers

Observations that depart considerably from the center of a distribution demand special consideration. They may be retained, trimmed, or weighted less than other data. This article provides a BASIC program that implements Mosteller and Tukey’s (1977) technique for weighting observations less as they depart from the middle of a distribution. Influence curves for this “bisquare-weighted mean,” or “bimean,” are displayed and compared with more traditional measures of central tendency.