[R] CI with sd

[Chuck Cleland]

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.
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