> On Mar 23, 2016, at 1:44 PM, ruipbarra...@sapo.pt wrote: > > Hello, > > Try > > ?t.test > t.test(mA, mB, alternative = "greater") > > Hope this helps, > > Rui Barradas > > > Citando Eliza Botto <eliza_bo...@outlook.com>: > >> Dear All, >> I want to test a hypothesis in R by using student' t-test (P-values). >> The hypothesis is that model A produces lesser error than model B at >> ten stations. Obviously, Null Hypothesis (H0) is that the error >> produces by model A is not lower than model B.
NOT "obviously". You only get to do one-sided tests when the scientific question would not allow the possibility of a departure to "the other side". Two-sided tests are the norm in scientific literature, often to the experimenter's distress when they haven't done a thoughtful (non-optimistic) power analysis and their results are inconclusive as a result. Your hypothesis _should_ have been constructed _before_ you saw the data. That is if you want to be an ethical scientist. >> The error magnitudes are >> >> #model A >>> dput(mA) >> >> c(36.1956086452583, 34.9996207622861, 36.435733025221, >> 37.2003157636202, 36.1318687775115, 37.164132533536, >> 35.2028759357069, 36.7719835944373, 38.3861425339751, >> 37.4174132119744) >> #model B >>> dput(mB) >> >> c(39.7655211768704, 40.1730916643841, 39.3699055738618, >> 39.401619831763, 41.1218634441457, 39.1968630742826, >> 40.5265825061639, 40.4674956975404, 40.5954427072364, >> 41.4875529130543) Those are not models. They are just vectors of numbers. And they seem unlikely to be residual errors of a linear model since they are not centered on zero. I doubt there is enough in your presentation for a sensible comment on the proper analysis. -- David. >> >> Now can I test my hypothesis in R? >> Thankyou very much in Advance, >> Eliza >> [[alternative HTML version deleted]] >> >> ______________________________________________ David Winsemius Alameda, CA, USA ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
