[R] Ayuda con un árbol de regresión

[Jose Iparraguirre]

Miguel,

Sin tus datos es imposible brindarte una respuesta precisa pero ten en cuenta que la descripción del argumento 'fórmula' en la función tree del paquete del mismo nombre dice que la variable dependiente -PRECIO en tu caso- debe ser un vector numérico si quieres estimar un árbol de regressión o un factor si deseas producir un árbol de clasificación. No veo términos de interacción en tu fórmula, cuya presencia no es permitida, por lo que te sugiero revises qué clase de objeto es PRECIO, para lo cual puedes escribir str(CARROST$PRECIO). Puede que necesites modificar la clase a vector numérico.

Without any of your data we can't give you a precise answer, but take into account that the description of the formula argument of the tree function (package tree) reads: "The left-hand-side (response) should be either a numerical vector when a regression tree will be fitted or a factor, when a classification tree is produced. The right-hand-side should be a series of numeric or factor variables separated by +; there should be no interaction terms". Your formula contains no interaction terms, so I'd suggest you should check what class of object PRECIO is -type str(CARROST$PRECIO). You may need to change it to a numerical vector.

José



-----Original Message-----
From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Michael Dewey
Sent: 24 March 2015 18:16
To: Miguel angel Lopez Martinez; r-help at r-project.org
Subject: Re: [R] Ayuda con un árbol de regresión

Miguel, si prefieres escribir en espanol

https://stat.ethz.ch/mailman/listinfo/r-help-es

(This is the address of the Spanish language mailing list)

On 23/03/2015 20:13, Miguel angel Lopez Martinez wrote:
> ARBOL<-tree(PRECIO~CILINDRAJE_DEL_MOTOR+MODELO,data=CARROST)
> ARBOL
> plot(ARBOL)
> text(ARBOL,cex=0.9)
>
>   este es el código que utilizamos las variables cilindraje y modelo 
> son categóricas transformadas por que si utilizamos las varibales como 
> factor no las reconoce
>
> 	[[alternative HTML version deleted]]
>
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--
Michael
http://www.dewey.myzen.co.uk

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