>>>>> AK writes: Thanks. What precisely is the problem you are seeing?
R uses Royston's ALGORITHM AS R94 APPL. STATIST. (1995) vol.44, no.4, 547-551 which in turn uses the improved approximations to the weights from <https://doi.org/10.1007/BF01891203>, and Table 1 in Hanusz et al would seem to suggest that they are indeed accurate to two significant digits? Best -k > Good afternoon, > This concerns the Shapiro-Wilk test for normal distribution in the field > of mathematical statistics. > Did you take into account the latest research findings from the 2014 > publication by Hanusz & Tarasińska (1) when calculating the coefficients > for the W-statistic? Both authors point out an error in the original > work by Shapiro and Wilk. > If you have not yet corrected the coefficient calculation, this could > lead to incorrect decisions in the case of the so-called H0 hypothesis. > I hope you find this helpful. > Best regards > Alexander Kud > (1) Zofia Hanusz & Joanna TarasiŃska (2014) Simulation Study on Improved > Shapiro–Wilk Tests for Normality, Communications in Statistics - > Simulation and Computation, 43:9, 2093-2105, DOI: > 10.1080/03610918.2013.844835 > Link to this article: http://dx.doi.org/10.1080/03610918.2013.844835 > Abstract > The article concerns tests for normality based on the Shapiro–Wilk W > statistic. The constants in the test statistic are recalculated as those > given in Shapiro and Wilk are incorrect. The empirical significance > levels and power of improved tests have been evaluated in simulation > study and compared to original ones. The improved tests were also > applied to the multivariate case. In this case, we consider two > implementations of the W statistic, the first one proposed by Srivastava > and Hui and the other by Hanusz and Tarasinska. Empirical size of tests > and their power have been compared to the Henze–Zirkler test. > --------------------------------------------------- > Dr. Alexander Kud > Scientist in Physical Chemistry > [email protected] > --------------------------------------------------- > x[DELETED ATTACHMENT OpenPGP_signature.asc, application/pgp-signature] > ______________________________________________ > [email protected] mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
