From ripley at stats.ox.ac.uk  Wed Feb 25 14:19:15 2009
From: ripley at stats.ox.ac.uk (Prof Brian Ripley)
Date: Wed, 25 Feb 2009 13:19:15 +0000 (GMT)
Subject: [Rd] [R] length 1 offset in glm (& lm)
In-Reply-To: <20090225141510.vzf0j0passoso4sw@imp.inserm.fr>
References: <49A53E1B.4090004@warwick.ac.uk>
	<alpine.OSX.1.00.0902251252010.70608@tystie.local>
	<20090225141510.vzf0j0passoso4sw@imp.inserm.fr>
Message-ID: <alpine.OSX.1.00.0902251316340.70608@tystie.local>

On Wed, 25 Feb 2009, Kenneth Knoblauch wrote:

> Hi
>
> Quoting Prof Brian Ripley <ripley at stats.ox.ac.uk>:
>
>> On Wed, 25 Feb 2009, Heather Turner wrote:
>> 
>>> This post about length 1 offsets on R help seems to have been ignored
>>> (sorry deleted original email - is there a way to continue thread in
>>> this case?)
>>> 
>>> https://stat.ethz.ch/pipermail/r-help/2009-February/189352.html
>> 
>> So let's be clear: this was the 'offset' argument' and not the offset()
>> function as you refer to below.
>
> It occurs for both

Yes (I knew). but no one (AFAICS) said the function allows length-1 
arguments: Heather is raising the possibility that it should as new 
functionality, I believe.

> c1 <- structure(list(Contr = c(0.028, 0.043, 0.064, 0.097, 0.146, 0.219
> ), Correct = c(34L, 57L, 94L, 152L, 160L, 160L), Incorrect = c(126L,
> 103L, 66L, 8L, 0L, 0L)), .Names = c("Contr", "Correct", "Incorrect"
> ), row.names = c(NA, 6L), class = "data.frame")
>
> glm(cbind(Correct, Incorrect) ~ Contr + offset(qlogis(0.25)) - 1, binomial,
> 	data = c1)
> Error in model.frame.default(formula = cbind(Correct, Incorrect) ~ Contr +  :
> variable lengths differ (found for 'offset(qlogis(0.25))')
> +
>
> Thanks for looking into this when time permits.
>
> Ken
>
> --- remaining deleted

> -- 
> Ken Knoblauch
> Inserm U846
> Stem-cell and Brain Research Institute
> Department of Integrative Neurosciences
> 18 avenue du Doyen L?pine
> 69500 Bron
> France
> tel: +33 (0)4 72 91 34 77
> fax: +33 (0)4 72 91 34 61
> portable: +33 (0)6 84 10 64 10
> http://www.sbri.fr/members/kenneth-knoblauch.html
>

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595


[Rd] [R] length 1 offset in glm (& lm)
Prof Brian Ripley