[R] GAM

[Simon Wood]

Kilometres has only 5 unique values, while Bonus has only 7, but the 
default smoothing basis dimension for the s terms is 10, so there is a 
problem. Solution is to reduce the basis dimension. e.g.

amgam <- gam(log(Payment) ~ offset(log(Insured))+
+ s(as.numeric(Kilometres),k=5) + s(Bonus,k=7) + Make + s(Claims),family 
= gaussian,
+ data = motori)


On 08/11/11 16:57, Gyanendra Pokharel wrote:
> Hi R community!
> I am analyzing the data set "motorins" in the package "faraway" by using
> the generalized additive model. it shows the following error. Can some one
> suggest me the right way?
>
> library(faraway)
> data(motorins)
> motori<- motorins[motorins$Zone==1,]
> library(mgcv)
>> amgam<- gam(log(Payment) ~ offset(log(Insured))+
> s(as.numeric(Kilometres)) + s(Bonus) + Make + s(Claims),family = gaussian,
> data = motori)
> Error in smooth.construct.tp.smooth.
> spec(object, dk$data, dk$knots) :
>    A term has fewer unique covariate combinations than specified maximum
> degrees of freedom
>> summary(amgam)
> Error in summary(amgam) : object 'amgam' not found
> Gyan
>
> 	[[alternative HTML version deleted]]
>
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-- 
Simon Wood, Mathematical Science, University of Bath BA2 7AY UK
+44 (0)1225 386603               http://people.bath.ac.uk/sw283