Thank you a lot for the update. I understand leaving NaN/NA in these cases, that can make sense. But feels to me that this situation could maybe produce a warning, to inform the user of what had happened?
Kind regards, Karolis K. > On Jan 24, 2021, at 6:52 PM, Kurt Hornik <kurt.hor...@wu.ac.at> wrote: > >>>>>> Karolis K writes: > >> To me it seems like returning chi-sq = 0 and p-value = 1 would make sense. >> It would also be consistent with other scenarios of equal variance in all >> groups. One example: > >> fligner.test(1:8, gl(2,4)) >> # Fligner-Killeen test of homogeneity of variances >> # >> # data: 1:8 and gl(2, 4) >> # Fligner-Killeen:med chi-squared = 0, df = 1, p-value = 1 > >> But I am aware that other tests implemented in stats:: sometimes throw >> errors in similar situations. > >> Maybe someone more familiar with the behaviour and philosophy behind >> stats:: preferences can add more weight here? > > Thanks for spotting this. After some internal discussions, we've come > to the conclusion that there is no "obvious" way to handle situations > where the Fligner-Killeen:med chi-squared test statistic is undefined > (i.e., when the denominator is zero). [Owing to the discreteness of the > ranks, trying to take limits will not work.] For now, these > sitatuations consistently give NaN/NA instead of errors (and the numeric > computations were improved so that it should no longer possible to get a > zero denominator and a non-zero numerator). > > Best > -k > >> Warm regards, >> Karolis K. > >> [[alternative HTML version deleted]] > >> ______________________________________________ >> R-devel@r-project.org <mailto:R-devel@r-project.org> mailing list >> https://stat.ethz.ch/mailman/listinfo/r-devel >> <https://stat.ethz.ch/mailman/listinfo/r-devel> [[alternative HTML version deleted]] ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
