Indeed, this is what I wanted, I figured it from the function you and Mark pointed me. Thank you both.
I am trying to plot it to illustrate the point and I tried this plot(function(x) dt(x, df = 9), -5, 5, ylim = c(0, 0.5), main="t - Density", yaxs="i") Is there an easy way to shade the area under the curve? -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Wednesday, August 01, 2007 3:18 PM To: [EMAIL PROTECTED]; r-help@stat.math.ethz.ch Subject: Re: [R] t-distribution Well, is "t = 1.11" all that accurate in the first place? :-) In fact, reading beween the lines of the original enquiry, what the person probably wanted was something like ta <- pt(-1.11, 9) + pt(1.11, 9, lower.tail = FALSE) which is the two-sided t-test tail area. The teller of the parable will usually leave some things unexplained... Bill. Bill Venables CSIRO Laboratories PO Box 120, Cleveland, 4163 AUSTRALIA Office Phone (email preferred): +61 7 3826 7251 Fax (if absolutely necessary): +61 7 3826 7304 Mobile: +61 4 8819 4402 Home Phone: +61 7 3286 7700 mailto:[EMAIL PROTECTED] http://www.cmis.csiro.au/bill.venables/ -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ben Bolker Sent: Thursday, 2 August 2007 4:57 AM To: r-help@stat.math.ethz.ch Subject: Re: [R] t-distribution <Bill.Venables <at> csiro.au> writes: > > for the upper tail: > > > 1-pt(1.11, 9) > [1] 0.1478873 > wouldn't pt(1.11, 9, lower.tail=FALSE) be more accurate? ______________________________________________ R-help@stat.math.ethz.ch 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@stat.math.ethz.ch 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@stat.math.ethz.ch 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.
