From: francogrex <francogrex_at_mail.com>

Date: Fri, 18 May 2007 12:15:02 -0700 (PDT)

Date: Fri, 18 May 2007 12:15:02 -0700 (PDT)

At the alpha level you set, A is neither greater nor less than B. Supposing
you don't use paired t.test:

data: c(10, 20, 30) and c(25, 30, 15)

t = -0.4588, df = 3.741, p-value = 0.6717
alternative hypothesis: true difference in means is not equal to 0
95 percent confidence interval:

-24.06675 17.40008

sample estimates:

mean of x mean of y

20.00000 23.33333

it tells you what is the null and what is the alternative.

genomenet wrote:

*>
*

> Hi There,

*> Using t.test to test hypothesis about which one is greater, A or B?
**> where A={10,20,30},B={25,30,15}.
**> My question is which of the following conclusions is right?
**> #################hypothesis testing 1
**> h0: A greater than or equal to B
**> h1: A less than B
**> below is splus code
**> A=c(10,20,30)
**> B=c(25,30,15)
**> t.test(c(10,20,30),c(25,30,15),alternative="less")
**> output:
**> p-value=0.3359
**> because p-value is not less than alpha (0.05), we
**> cannot reject h0.
**> so A greater than or equal to B.
**> #################hypothesis testing 2
**> h0: A less than or equal to B
**> h1: A greater than B
**> below is splus code
**> A=c(10,20,30)
**> B=c(25,30,15)
**> t.test(c(10,20,30),c(25,30,15),alternative="greater")
**> output:
**> p-value=0.6641
**> because p-value is not less than alpha (0.05), we
**> cannot reject h0.
**> so A less than or euqal to B.
**> #########################################
**> Thank you very much.
**> Van
**>
*

-- View this message in context: http://www.nabble.com/%7B10%2C20%2C30%7D%3E%3D%7B25%2C30%2C15%7D-tf3779346.html#a10688603 Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help_at_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.Received on Fri 18 May 2007 - 19:28:09 GMT

Archive maintained by Robert King, hosted by
the discipline of
statistics at the
University of Newcastle,
Australia.

Archive generated by hypermail 2.2.0, at Fri 18 May 2007 - 19:31:56 GMT.

*
Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-help.
Please read the posting
guide before posting to the list.
*