Thanks Kent and Petr, the problem was indeed the "C"/missing value that I
had to convert!

Thanks Peter too, the "factor" explanation will also be quite usefull for
further work.

Best regards,
Thibault

On 11 April 2011 03:48, Rolf Turner <rolf.turner@xtra.co.nz> wrote:

> On 11/04/11 10:08, Peter Ehlers wrote:
>
> <SNIP>
>
>  "Checking" anything with Excel is never much use.
>>
>
> <SNIP>
>
> Fortune?
>
>    cheers,
>
>        Rolf Turner
>
>
> ______________________________________________
> R-help@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.
>

	[[alternative HTML version deleted]]

