Message-ID: <004801c05a2f$3e11f1a0$c4c8c284@cudenver.edu>
Date: 2000-11-29T18:07:31Z
From: Matt Pocernich
Subject: Step function
I am having problem using the step function for a linear regression model. I've created an initial model containing only the intercept. Then using the step function, I've selected three variables to be considered for the model.
> x0.lm<- lm(MEDV~1, data = x)
>
> anova(x0.lm)
Analysis of Variance Table
Response: MEDV
Df Sum Sq Mean Sq F value Pr(>F)
Residuals 505 42716 85
>
> step(x0.lm, ~ CRIM + ZN + RM)
Start: AIC= 2246.51
MEDV ~ 1
Error in eval(expr, envir, enclos) : Object "MEDV" not found
>
I am not clear as to why the MEDV object ( the variable I am trying to predict) is not found. I receive an identical message using the command > step(x0.lm).
I am using R version 1.1.1. I can run all the examples successfully. Also, I realize that there are differences in the algorithms, but I can run the code above on Splus version 5.
Thanks
Matt Pocernich
-------------- next part --------------
An HTML attachment was scrubbed...
URL: https://stat.ethz.ch/pipermail/r-help/attachments/20001129/2f219ad5/attachment.html