help fprank-------------------------------------------------------------------------------

Title

fprank-- Two-Sample Fligner-Policello Robust Rank Order Test

Syntax

fprankvarname[if] [in],by(groupvar)

optionsDescription ------------------------------------------------------------------------- Main *by(groupvar)grouping variable ------------------------------------------------------------------------- *by(groupvar)is required.bymay be used with the above commands; seeby.

Description

fpranktests the hypothesis that two independent groups are sampled from the same population using the robust rank-order test which is a useful alternative of the Mann-Whitney-Wilcoxon test for non-normal populations with unequal variances. This test assumes neither normality, nor equal variances, nor equal shape.

fprankprovides the asymptotic p-value which is based on the standard normal distribution. It should be noted, however, that the asymptotic p-value may not be adequate when both samples are <= 12. To obtain the significance of the statistic U when sample sizes are (<=12), refer to the table of critical Values of U for the robust rank order test found in the references below.

Examples

. fprank scores, by(group)ReferencesSiegel, S. & Castellan, N.J.Jr.(1988).

Nonparametric statistics for thebehavioral sciences(2nd ed.). New York: McGraw-Hill.Hollander, M & Wolfe, DA. (1999).

Nonparametric statistical methods(2nd ed.). New York: Wiley.Fligner, MA & Policello, GE. (1981). Robust rank procedures for the Behrens-Fisher problem.

Journal of the American Statistical Association,76(373), 162-168.The two data files attached to this package are from Siegel & Castellan (1988, pp 138-143).

AuthorBenmamoun, Mamoun, Saint Louis University , Saint Louis, MO, U.S.A. Email vmamoun@yahoo.com if you observe any problem or if you have any comment or question.

Also SeeOnline:

ranksum,ttest