# Re: [R] binom.test

From: Ethan Johnsons <ethan.johnsons_at_gmail.com>
Date: Thu 19 Oct 2006 - 16:00:24 GMT

Thx much for the feedback.
It is a big help.

ej

On 10/19/06, Ted Harding <Ted.Harding@nessie.mcc.ac.uk> wrote:
> On 19-Oct-06 Ethan Johnsons wrote:
> > R-experts:
> >
> > A quick question, please.
> >
> >>From a lab exp, I got 12 positives out of 50.
> > To get 90% CI for this , I think binom.test might be
> > the one to be used.
> > Is there a better way or function to calculate this?
>
> What do you mean by "better"? For a symmetrical 2-sided
> exact binomial confidence interval, binom.test gives the
> result quickly and, to within the precision of pbinom,
> correctly (as I've just verified by hand!).
>
> And you can get 1-sided CIs by setting the 'alternative'
> option, or asymmetrical CI's by finding the two 1-sided
> CIs (e.g. for conf.level = 0.03 and 0.07) that you want.
>
> What do you want to improve on?
>
> >> binom.test(x=12, n=50, p=12/50, conf.level = 0.90)
> >
> > Exact binomial test
> >
> > data: 12 and 50
> > number of successes = 12, number of trials = 50, p-value = 1
> > alternative hypothesis: true probability of success is not equal to
> > 0.24
> > 90 percent confidence interval:
> > 0.1447182 0.3596557
>
> r<-12 ; n<-50
>
> 1-pbinom(r-1,n, 0.14471815)
> [1] 0.04999999
>
> 1-pbinom(r-1,n, 0.14471816)
> [1] 0.05000001
>
>
> pbinom(r,n, 0.35965569)
> [1] 0.05000001
>
> pbinom(r,n, 0.35965570)
> [1] 0.05
>
> pbinom(r,n, 0.35965571)
> [1] 0.04999998
>
>
> > sample estimates:
> > probability of success
> > 0.24
> >
> > thx much
> >
> > ej
>
> Best wishes,
> Ted.
>
> --------------------------------------------------------------------
> E-Mail: (Ted Harding) <Ted.Harding@nessie.mcc.ac.uk>
> Fax-to-email: +44 (0)870 094 0861
> Date: 19-Oct-06 Time: 16:53:19
> ------------------------------ XFMail ------------------------------
>

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