Thank you so much. I see your point. ej
On 10/20/06, Petr Pikal <[EMAIL PROTECTED]> wrote: > Hi > > On 19 Oct 2006 at 13:19, Ethan Johnsons wrote: > > Date sent: Thu, 19 Oct 2006 13:19:40 -0400 > From: "Ethan Johnsons" <[EMAIL PROTECTED]> > To: "Chuck Cleland" <[EMAIL PROTECTED]> > Copies to: [email protected] > Subject: Re: [R] CI with sd > > > 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%? > > With some sd value and assuming normal distribution > > 26.2+qnorm(.95)*sd/sqrt(250) > 26.2-qnorm(.95)*sd/sqrt(250) > > as you can find in statistical textbooks. > > But without having sd value? > > HTH > Petr > > > > > > thx much, > > > > ej > > > > On 10/19/06, Chuck Cleland <[EMAIL PROTECTED]> 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 > > > > > > > > ______________________________________________ > > > > [email protected] 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. > > > > > > -- > > > Chuck Cleland, Ph.D. > > > NDRI, Inc. > > > 71 West 23rd Street, 8th floor > > > New York, NY 10010 > > > tel: (212) 845-4495 (Tu, Th) > > > tel: (732) 512-0171 (M, W, F) > > > fax: (917) 438-0894 > > > > > > > > > > ______________________________________________ > > [email protected] 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. > > Petr Pikal > [EMAIL PROTECTED] > > ______________________________________________ [email protected] 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.
