[R] CI with sd

[Ethan Johnsons]

I thought of another interesting scenario, and I would just go ahead
and ask this.
I have a mean (i.e. 26.2) where the number of e coli samples is 250.
The mean is already calculated, so it is a discrete value, not series.

What fucntion can be used for the calc with CI i.e. 90%?

thx much,

ej

On 10/19/06, Chuck Cleland <ccleland at optonline.net> wrote:
> Ethan Johnsons wrote:
> > Please let me ask you another quick question.
> > I have results for e coli, and am trying to get 95% CI with the sd (1.783956).
> > I got the result from another tool as (1.21, 3.42).
> > But, I like to verify it with R.  What function do you use for this?
> >
> >> e.coli=c(27.5,24.6,25.3,28.7,23,26.8,24.7,24.3,24.9)
> >> sd(e.coli, na.rm = FALSE)
> > [1] 1.783956
> >
> > Sorry for the newbie question.
>
> e.coli <- c(27.5,24.6,25.3,28.7,23,26.8,24.7,24.3,24.9)
> library(nlme)
> mod1 <- gls(e.coli ~ 1)
> intervals(mod1)
>
> Approximate 95% confidence intervals
>
>  Coefficients:
>                lower     est.    upper
> (Intercept) 24.16206 25.53333 26.90460
> attr(,"label")
> [1] "Coefficients:"
>
>  Residual standard error:
>    lower     est.    upper
> 1.204986 1.783956 3.417651
>
> > thx much
> >
> > ej
> >
> > ______________________________________________
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>
> --
> Chuck Cleland, Ph.D.
> NDRI, Inc.
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