Hi everyone, How to search t value when you know degree of freedom? For example, the degree of freedom is 29, how to use R to calculate the t value for it? t.test does not help, or pnorm? I am not sure. Thanks.
How to search t value when you know degree of freedom?
5 messages · vod vos, Rui Barradas, Michael Dewey +1 more
Hello, It would be ?pt not pnorm. And as you can see in that help page you need another value, the value of the quantile. (Don't worry about the arguments ncp or log just q and df) Hope this helps, Rui Barradas Em 22-02-2017 15:53, vod vos escreveu:
Hi everyone, How to search t value when you know degree of freedom? For example, the degree of freedom is 29, how to use R to calculate the t value for it? t.test does not help, or pnorm? I am not sure. Thanks.
______________________________________________ R-help at 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.
If we want to get 95% limit of t value, the result will be pt(0.975, 29) = 2.045 is that right? ---- On ???, 22 ?? 2017 08:04:36 -0800 Rui Barradas <ruipbarradas at sapo.pt> wrote ---- > Hello, > > It would be ?pt not pnorm. > And as you can see in that help page you need another value, the value > of the quantile. (Don't worry about the arguments ncp or log just q and df) > > Hope this helps, > > Rui Barradas > > Em 22-02-2017 15:53, vod vos escreveu: > > > > Hi everyone, > > > > How to search t value when you know degree of freedom? > > > > For example, the degree of freedom is 29, how to use R to calculate the t value for it? > > > > t.test does not help, or pnorm? I am not sure. > > > > Thanks. > > > > ______________________________________________ > > R-help at 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. > > >
When I do pt(0.975, 29) I do not get 2.045 so I think you must have declared a new function pt which is interfering with things.
On 23/02/2017 10:40, vod vos wrote:
If we want to get 95% limit of t value, the result will be pt(0.975, 29) = 2.045 is that right? ---- On ???, 22 ?? 2017 08:04:36 -0800 Rui Barradas <ruipbarradas at sapo.pt> wrote ----
> Hello, > > It would be ?pt not pnorm. > And as you can see in that help page you need another value, the value > of the quantile. (Don't worry about the arguments ncp or log just q and df) > > Hope this helps, > > Rui Barradas > > Em 22-02-2017 15:53, vod vos escreveu:
> > > > Hi everyone, > > > > How to search t value when you know degree of freedom? > > > > For example, the degree of freedom is 29, how to use R to calculate the t value for it? > > > > t.test does not help, or pnorm? I am not sure. > > > > Thanks. > > > > ______________________________________________
> > R-help at 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. > >
>
______________________________________________ R-help at 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.
Perhaps a typo? It should be qt() not pt():
pt(0.975, 29)
[1] 0.8311882
qt(0.975, 29)
[1] 2.04523 ------------------------------------- David L Carlson Department of Anthropology Texas A&M University College Station, TX 77840-4352 -----Original Message----- From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Michael Dewey Sent: Thursday, February 23, 2017 6:18 AM To: vod vos <vodvos at zoho.com>; Rui Barradas <ruipbarradas at sapo.pt> Cc: R-help at r-project.org Subject: Re: [R] How to search t value when you know degree of freedom? When I do pt(0.975, 29) I do not get 2.045 so I think you must have declared a new function pt which is interfering with things.
On 23/02/2017 10:40, vod vos wrote:
If we want to get 95% limit of t value, the result will be pt(0.975, 29) = 2.045 is that right? ---- On ???, 22 ?? 2017 08:04:36 -0800 Rui Barradas <ruipbarradas at sapo.pt> wrote ----
> Hello, > > It would be ?pt not pnorm. > And as you can see in that help page you need another value, the value > of the quantile. (Don't worry about the arguments ncp or log just q and df) > > Hope this helps, > > Rui Barradas > > Em 22-02-2017 15:53, vod vos escreveu:
> > > > Hi everyone, > > > > How to search t value when you know degree of freedom? > > > > For example, the degree of freedom is 29, how to use R to calculate the t value for it? > > > > t.test does not help, or pnorm? I am not sure. > > > > Thanks. > > > > ______________________________________________
> > R-help at 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. > >
>
______________________________________________ R-help at 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.
Michael http://www.dewey.myzen.co.uk/home.html ______________________________________________ R-help at 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.