[R] Fit Gompertz' curve'

[Dennis Murphy]

Hi:

On Tue, Aug 16, 2011 at 7:07 AM, Silvano <silvano at uel.br> wrote:
> Hi,
>
> I build a graph taking into account the times: 1,
> 2,4,6,8,10,12,15,18,21,24,28,32 and 48.
>
> Be that the scale of the X axis does not look right. It seems equidistant.
> (graph attached)

(a) No graph came through. See the Posting Guide for details of what
types of attachments will pass to the list.

(b) Is Tempo numeric or factor? Try str(mydataframename) to find out
the classes of each variable in your data frame. If they seem
equidistant, it's a plausible null hypothesis that Tempo is a factor.
If so, change it to numeric; one way to do this is

mydataframe$tempo <- as.numeric(as.character(mydataframe$Tempo))

I used a different variable name so that you can double check whether
the conversion is correct. Also run str() on the modified data to make
sure that the new variable is numeric.

HTH,
Dennis
>
> What changes have I to do in the following commands so that the scale be
> correct?
>
> interaction.plot(Tempo, Trat, Valor, ylim=c(0, 2), las=1,
>                lty=c(1,2,3,4), lwd=3, bty='l',
>                col=c('red','blue','magenta','green'),
>                ylab="Média de Gases", xlab="Tempo (h)",
>                trace.label="Doses")
>
> Thanks,
>
> --------------------------------------
> Silvano Cesar da Costa
> Departamento de Estatística
> Universidade Estadual de Londrina
> Fone: 3371-4346
> --------------------------------------
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