{smcl}
{* 18mar2005}{...}
{cmd:help fprank}
{hline}

{title:Title}

{p2colset 5 15 17 2}{...}
{p2col :{hi:fprank} {hline 2}}Two-Sample Fligner-Policello Robust Rank Order Test {p_end}
{p2colreset}{...}

{title:Syntax}

{p 8 19 2}
{cmd:fprank} {varname} {ifin}{cmd:,} {cmd:by(}{it:groupvar}{cmd:)} 

{synoptset 21 tabbed}{...}
{synopthdr:options}
{synoptline}
{syntab:Main}
{p2coldent:* {opt by(groupvar)}}grouping variable{p_end}
{synoptline}
{p2colreset}{...}
{p 4 6 2}* {opt by(groupvar)} is required.{p_end}
{p 4 6 2}{opt by} may be used with the above commands;
see {helpb by}.{p_end}

{title:Description}

{pstd}
{cmd:fprank} tests 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. 

{pstd}
{cmd:fprank} provides 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.  

{title:Examples}

{psee}{cmd:. fprank scores, by(group)}{p_end}
	
{title:References} 

 {p 4 4 2}Siegel, S. & Castellan, N.J.Jr.(1988). {it}Nonparametric statistics for the behavioral sciences {sf} (2nd ed.). New York: McGraw-Hill.

{p 4 4 2}Hollander, M & Wolfe, DA. (1999). {it}Nonparametric statistical methods {sf} (2nd ed.). New York: Wiley.

{p 4 4 2}Fligner, MA & Policello, GE. (1981). Robust rank procedures for the Behrens-Fisher problem. {it}Journal of the American Statistical Association, 
{sf} 76(373), 162-168.

{p 4 4 2}The two data files attached to this package are from Siegel & Castellan (1988, pp 138-143).

{title:Author} 

{p 4 4 2}Benmamoun, Mamoun, Saint Louis University , Saint Louis, MO, U.S.A. 
Email {browse "mailto: vmamoun@yahoo.com": vmamoun@yahoo.com} if you observe any problem or if you have any comment or question.

{title:Also See}

{psee}
Online:  {helpb ranksum}, {helpb ttest} {p_end}