[R] Re: logistic regression {R-help Digest ..}

[David Duffy]

On Tue, 9 Sep 2003 Christoph Lehmann <christoph.lehmann at gmx.ch> wrote:
> I have the following data
>           V1 V2
> 1 -5.8000000  0
> 2 -4.8000000  0
> 3 -2.8666667  0
> 4 -0.8666667  0
> 5 -0.7333333  0
> 6 -1.6666667  0
> 7 -0.1333333  1
> 8  1.2000000  1
> 9  1.3333333  1
> 
> and I want to know, whether V1 can predict V2: of course it can, since
> there is a perfect separation between cases 1..6 and 7..9
> 
> How can I test, whether this conclusion (being able to assign an
> observation i to class j, only knowing its value on Variable V1)  holds
> also for the population, our data were drawn from? 

The brlr package does this:

summary(brlr(V2 ~ V1))

brlr(formula = V2 ~ V1)
 
Coefficients:
            Value  Std. Error t value
(Intercept) 0.2620 1.0624     0.2466
V1          1.4014 1.0077     1.3908
 
Deviance: 3.5078
Penalized deviance: 3.528
Residual df: 7


-- 
| David Duffy (MBBS PhD)                                         ,-_|\
| email: davidD at qimr.edu.au  ph: INT+61+7+3362-0217 fax: -0101  /     *
| Epidemiology Unit, Queensland Institute of Medical Research   \_,-._/
| 300 Herston Rd, Brisbane, Queensland 4029, Australia  GPG 4D0B994A v