Hi, seems as if you want to test if a single subject is a member of a population from which you have drawn a sample. This question has been addressed by Payne & Jones and Crawford and collaborators. You should have a look at their articles in case that I interpreted your null-hypothesis and data in the correct way....
Good luck, Thilo Payne & Jones (1957, J Clin Psychol 13:115-121) Crawford, Howell, Garthwaite (1998, J Clin Exp Neurosychol 12:482) Crawford JR, Garthwaite PH (2005) Evaluation of Criteria for Classical Dissociations in Single-Case Studies by Monte Carlo Simulation. Neuropsychology 19(5): 664-678) On Thursday 23 November 2006 14:48, Peter Dalgaard wrote: > "ONKELINX, Thierry" <[EMAIL PROTECTED]> writes: > > There is no such thing as an unpaired t-test. A t-test can be a paired, > > one sample or two sample t-test. Since you want to compare the sample > > against a given mean, you need a one sample t-test. You tried to do a > > two sample test. That didn't work because you need at least two > > observations in each group. > > NO! This is just plain wrong. > > > x <- c(23,25,29,27,30,30) > > t.test(x[-1], mu = x[1]) > > > > One Sample t-test > > > > data: x[-1] > > t = 5.3634, df = 4, p-value = 0.005833 > > alternative hypothesis: true mean is not equal to 23 > > 95 percent confidence interval: > > 25.50814 30.89186 > > sample estimates: > > mean of x > > 28.2 > > > > > > Cheers, > > > > Thierry > > > > ------------------------------------------------------------------------ > > ---- > > > > ir. Thierry Onkelinx > > > > Instituut voor natuur- en bosonderzoek / Reseach Institute for Nature > > and Forest > > > > Cel biometrie, methodologie en kwaliteitszorg / Section biometrics, > > methodology and quality assurance > > > > Gaverstraat 4 > > > > 9500 Geraardsbergen > > > > Belgium > > > > tel. + 32 54/436 185 > > > > [EMAIL PROTECTED] > > > > www.inbo.be > > > > > > > > Do not put your faith in what statistics say until you have carefully > > considered what they do not say. ~William W. Watt > > > > A statistical analysis, properly conducted, is a delicate dissection of > > uncertainties, a surgery of suppositions. ~M.J.Moroney > > > > -----Oorspronkelijk bericht----- > > Van: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] Namens Robin Hankin > > Verzonden: donderdag 23 november 2006 14:12 > > Aan: [EMAIL PROTECTED] > > Onderwerp: [R] t.test() > > > > Hi > > > > I have a vector x of length n. I am interested in x[1] > > being different from the other observations (ie x[-1]). > > > > My null hypothesis is that x[1] > > is drawn from a Gaussian distribution of the same > > mean as observations x[-1], which are assumed > > to be iid Gaussian. The (unknown) variance > > of x[1] is assumed to be the same as the > > variance of x[-1]. > > > > > > This should be an unpaired t-test. > > > > But > > > > > x <- c(23,25,29,27,30,30) > > > t.test(x=x[1] , y=x[-1]) > > > > Error in t.test.default(x = x[1], y = x[-1]) : > > not enough 'x' observations > > > > > > > > > > What arguments do I need to send to t.test() to test my null? > > > > > > > > > > > > > > > > -- > > Robin Hankin > > Uncertainty Analyst > > National Oceanography Centre, Southampton > > European Way, Southampton SO14 3ZH, UK > > tel 023-8059-7743 > > > > ______________________________________________ > > [email protected] 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. > > > > ______________________________________________ > > [email protected] 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. -- ________________________ Thilo Kellermann Department of Psychiatry und Psychotherapy RWTH Aachen University Pauwelstr. 30 52074 Aachen Tel.: +49 (0)241 / 8089977 Fax.: +49 (0)241 / 8082401 E-Mail: [EMAIL PROTECTED] ______________________________________________ [email protected] 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.
