[R] Odp: Creating Dummy Variables in R

[Petr PIKAL]

Hi

r-help-bounces at r-project.org napsal dne 16.12.2009 15:58:56:

> Hi,
> I am trying to create a set of dummy variables to use within a multiple 
linear
> regression and am unable to find the codes within the manuals.
> 
> For example i have:
> Price     Weight     Clarity
>                              IF      VVS1    VVS2
> 500        8             1         0          0
> 1000      5.2          0         0          1
> 864        3              0        1          0
> 340        2.6          0         0          1
> 90          0.5          1         0          0 
> 450        2.3          0         1          0
> 
> Where price is dependent upon weight (single value in each observation) 
and 
> clarity (split into three levels, IF, VVS1, VVS2).
> I am having trouble telling the program that clarity is a set of 3 dummy 

> variables and keep getting error messages, what is the correct way?

Well, try to bribe it. Or ask what please it to break its resistance.

Seriously. What is a structure of your data in R.

?str

what commands did you use for regression

I suppose

lm(Price~Weight+IF+VVS1+VVS2, data=your.data)

shall not complain if your.data is a data frame.

Regards
Petr



> 
> Any helps is greatly appreciated.
> Matthew
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide 
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.