[R] R formula

Arne Henningsen arne.henningsen at googlemail.com
Tue Aug 18 13:21:17 CEST 2009

Hi Anwesha

On Tue, Aug 18, 2009 at 10:48 AM, Anwesha
Chakrabarti<c.anwesha at gmail.com> wrote:
> I was trying to estimate simultaneous equation system in R using systemfit.
> I used the following commands
>> library(systemfit)
>> data(Kmenta)
>> attach(Kmenta)
>> eqDemand<-consump~price+income
>> eqSupply<-consump~price+farmprice+trend

Please replace "farmprice" by "farmPrice"

>> fitsur<-systemfit("SUR",list(demand=eqDemand, supply=eqSupply))
> and got the following error messege
> Error in systemfit("SUR", list(demand = eqDemand, supply = eqSupply)) :
> argument 'formula' must be an object of class 'formula' or a list of objects
> of class 'formula'

The error message is correct. If you do not name the arguments, the
first argument must be the formula or the list of formulas. You could
estimate the system either by

R> fitsur <- systemfit( list( demand=eqDemand, supply=eqSupply ), "SUR" )

or by

R> fitsur <- systemfit( method="SUR", formula=list( demand=eqDemand,
supply=eqSupply ) )

Please read the documentation/manual of systemfit and the paper about
systemfit published in the JSS:


Best wishes,

Arne Henningsen

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