The small-sample properties of two non-parametric quantile regression estimators are compared. The first is based on constrained B-spline smoothing (COBS) and the other is based on a variation and slight extension of a running interval smoother. R functions for applying the methods were used in conjunction with default settings for the various optional arguments. Results indicate that the modified running interval smoother has practical value. Manipulation of the optional arguments might impact

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... the relative merits of the two methods, but the extent to which this is the case remains unknown.