Greg, I really like that TeachingDemos::SnowsPenultimateNormalityTest()… even the tortuous way to always return a p-value == 0:
# the following function works for current implementations of R # to my knowledge, eventually it may need to be expanded is.rational <- function(x){ rep( TRUE, length(x) ) } tmp.p <- if( any(is.rational(x))) { 0 } else { # current implementation will not get here if length # of x is positive. This part is reserved for the # ultimate test 1 } (p.value is then returned as tmp.p). Also, the nice and sexy printing of that p-value in R as: p-value < 2.2e-16 which looks much more serious than 'p-value = 0'… Here you has nothing to do. The stats::format.pval() function called from stats:::print.htest() already does the job for you! I am just curious… Are there teachers out there pointing to that test? If yes, what fraction of the students realise what happens? I guess, it is closer to zero than to one, unfortunately. Wait… I need another SnowsPenultimateXxxxTest() here to check the null hypothesis that all my students are doing what they are supposed to do when discovering a new statistical tool! Best, Philippe Grosjean On 21 Feb 2014, at 23:53, Greg Snow <538...@gmail.com> wrote: > Rui, > > Note this quote from the last paragraph of the Details section of ?ks.test: > > "If a single-sample test is used, the parameters specified in '...' > must be pre-specified and not estimated from the data." > > Which is the exact opposite of your example. > > > > Gonzalo, > > Why are you testing your data for normality? For large sample sizes > the normality tests often give a meaningful answer to a meaningless > question (for small samples they give a meaningless answer to a > meaningful question). > > If you really feel the need for a p-value then > SnowsPenultimateNormalityTest in the TeachingDemos package will work > for large sample sizes. But note that the documentation for that > function is considered more useful than the function itself. > > > > On Fri, Feb 21, 2014 at 3:04 PM, Rui Barradas <ruipbarra...@sapo.pt> wrote: >> Hello, >> >> Not answering directly to your question, if the sample size is a documented >> problem with shapiro.test and you want a normality test, why don't you use >> ?ks.test? >> >> m <- mean(HP_TrinityK25$V2) >> s <- sd(HP_TrinityK25$V2) >> >> ks.test(HP_TrinityK25$V2, "pnorm", m, s) >> >> >> Hope this helps, >> >> Rui Barradas >> >> Em 21-02-2014 15:59, Gonzalo Villarino Pizarro escreveu: >> >>> Dear R users, >>> Please help with with this maybe basic question. I am trying to see if my >>> data is normal but is a large file and the test does not work. >>> I keep getting the message : "Error in shapiro.test(x = HP_TrinityK25$V2) >>> : sample size must be between 3 and 5000" >>> thanks! >>> >>> shapiro.test(x=HP_TrinityK25$V2) >>> Error in shapiro.test(x = HP_TrinityK25$V2) : sample size must be between >>> 3 >>> and 5000 >>> >>> ##Note: >>> HP_TrinityK25= my file >>> HP_TrinityK25$V2= data in my file >>> >>> [[alternative HTML version deleted]] >>> >>> ______________________________________________ >>> R-help@r-project.org mailing list >>> https://stat.ethz.ch/mailman/listinfo/r-help >>> PLEASE do read the posting guide >>> http://www.R-project.org/posting-guide.html >>> and provide commented, minimal, self-contained, reproducible code. >>> >> >> ______________________________________________ >> R-help@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. > > > > -- > Gregory (Greg) L. Snow Ph.D. > 538...@gmail.com > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.