R help - May 2004 - results from t-test

Greetings,
I'm rather new to R, and only just subscribed to the mailing list.

I have run into a strange result in a t-test. The data represents the 
the hypothetical differences obtained for a t-test for dependent samples.

All the numeric output looks OK, but the statement that the alternative 
hypothesis is accepted seems rather strange.

 > data <- c(-6,6,-4,11,6,-3,-12,7,-1,4)
 > length(data)
 > t.test (data,mu=0)

         One Sample t-test

data:  data
t = 0.3548, df = 9, p-value = 0.7309
alternative hypothesis: true mean is not equal to 0
95 percent confidence interval:
  -4.300873  5.900873
sample estimates:
mean of x
       0.8

Can someone explain this? Beware though, I'm a forester and may not 
understand too technical explanations.

Patrick

F. Patrick Graz wrote:
> Greetings,
> I'm rather new to R, and only just subscribed to the mailing list.
> 
> I have run into a strange result in a t-test. The data represents the 
> the hypothetical differences obtained for a t-test for dependent samples.
> 
> All the numeric output looks OK, but the statement that the alternative 
> hypothesis is accepted seems rather strange.
> 
It doesn't say which hypothesis is accepted - the printed output just 
helps remind you what the alternative hypothesis is.  In this case, a 
p-value of 0.73 means you would be really, really safe sticking with the 
null hypothesis.

Cheers

Jason
(who is deliberately not dragging the professed non-statistician into 
the discussion we've had recently on the merits of p-values).  :)

On Sat, 01 May 2004 14:40:54 +0100, "F. Patrick Graz"
<pgraz at polytechnic.edu.na> wrote:
>All the numeric output looks OK, but the statement that the alternative 
>hypothesis is accepted seems rather strange.
I think you misread it.  It says
>alternative hypothesis: true mean is not equal to 0
which should be read as 

alternative hypothesis: "true mean is not equal to 0"

not

alternative hypothesis: true,  mean is not equal to 0

Duncan Murdoch