IMHO The difference makes sense for paired samples. For unpaired samples it is just the difference in means. I think presenting the means (and assuming the audience can perform subtraction) conveys more information. The interpretation of a difference of 5 might be influenced if I have means of -3, 2, or 4, 9, or 2000, 2005. Tim
-----Original Message----- From: R-help <r-help-boun...@r-project.org> On Behalf Of Samuel Granjeaud IR/Inserm Sent: Monday, April 3, 2023 7:25 AM To: PIKAL Petr <petr.pi...@precheza.cz>; r-help@r-project.org Subject: Re: [R] Should help of estimate in t.test be corrected? [External Email] Hi Thanks for your feedback. I didn't think about that. Still, the mean difference is computed for paired, not because there are two samples. IMHO, the help should be updated. Best, Samuel Le 2023-04-03 à 12:10, PIKAL Petr a écrit : > Hi > > You need to use paired option > >> t.test(x=0:4, y=sample(5:9), paired=TRUE)$estimate > mean difference > -5 > > Cheers > Petr > >> -----Original Message----- >> From: R-help <r-help-boun...@r-project.org> On Behalf Of Samuel >> Granjeaud IR/Inserm >> Sent: Sunday, April 2, 2023 11:39 PM >> To: r-help@r-project.org >> Subject: [R] Should help of estimate in t.test be corrected? >> >> Hi, >> >> Not important, but IMHO the estimate component of the t.test holds an >> estimate of mean of each group, never a difference. The doc says >> "estimate the estimated mean or difference in means depending on whether >> it >> was a one-sample test or a two-sample test." >> >> > t.test(0:4)$estimate >> mean of x >> 2 >> > t.test(0:4, 5:9)$estimate >> mean of x mean of y >> 2 7 >> >> Best, >> Samuel >> >> ______________________________________________ >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >> https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsta >> t.ethz.ch%2Fmailman%2Flistinfo%2Fr-help&data=05%7C01%7Ctebert%40ufl.e >> du%7Cdd06e263220c464ea0c908db3475a677%7C0d4da0f84a314d76ace60a62331e1 >> b84%7C0%7C0%7C638161452151623376%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4w >> LjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7 >> C&sdata=a7zlFppg4iG2uyMH7mpgyoLTIxXG8F3dx3FPt6YfLdc%3D&reserved=0 >> PLEASE do read the posting guide >> https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww. >> r-project.org%2Fposting-guide.html&data=05%7C01%7Ctebert%40ufl.edu%7C >> dd06e263220c464ea0c908db3475a677%7C0d4da0f84a314d76ace60a62331e1b84%7 >> C0%7C0%7C638161452151623376%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwM >> DAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sda >> ta=e%2B0jDRNJRJJ%2BE%2F091LZxD5%2BUhJAz%2FzSjJ7YZhYdFhDk%3D&reserved= >> 0 and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fstat.ethz.ch%2Fmailman%2Flistinfo%2Fr-help&data=05%7C01%7Ctebert%40ufl.edu%7Cdd06e263220c464ea0c908db3475a677%7C0d4da0f84a314d76ace60a62331e1b84%7C0%7C0%7C638161452151623376%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=a7zlFppg4iG2uyMH7mpgyoLTIxXG8F3dx3FPt6YfLdc%3D&reserved=0 PLEASE do read the posting guide https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.r-project.org%2Fposting-guide.html&data=05%7C01%7Ctebert%40ufl.edu%7Cdd06e263220c464ea0c908db3475a677%7C0d4da0f84a314d76ace60a62331e1b84%7C0%7C0%7C638161452151623376%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=e%2B0jDRNJRJJ%2BE%2F091LZxD5%2BUhJAz%2FzSjJ7YZhYdFhDk%3D&reserved=0 and provide commented, minimal, self-contained, reproducible code. ______________________________________________ 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.