(Re-) Read the docs (e.g. Intro to R, R Language Definition) . ...
arguments have to be named!
t.test(sleep$extra,mu=0, alt = "greater") ## works
-- Bert
On Wed, Jun 19, 2013 at 6:50 AM, Sparks, John James <jspark4 at uic.edu>
wrote:> Dear R Helpers,
>
> I am stuck on some syntax and I thought that I was following one of the
> examples that I found out there quite faithfully.
>
> I just want to know how to do a t test on a single mean for whether or not
> it is greater than a specific value. So I am using the data set sleep and
> I want to know if the mean of extra is greater then zero. I was under the
> impression that the syntax is
>
> t.test(sleep$extra,mu=0,"greater")
>
> but I get the error message
>
> Error in t.test.default(sleep$extra, mu = 0, "greater") :
> not enough 'y' observations
>
> I have tried this on a few other data sets that have more then 20
> observations and I get the same error. I looked in the documentation but
> the examples are for the comparison of two groups, not a single group
> mean.
>
> Any help would be most appreciated.
>
> --John J. Sparks, Ph.D.
>
> ______________________________________________
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> and provide commented, minimal, self-contained, reproducible code.
--
Bert Gunter
Genentech Nonclinical Biostatistics
Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm