[R] Help with lattice, regressions and respective lines - Correction

[Martin Henry H. Stevens]

Hi Jose,
I need to make a small correction in my code -
mod$data$B works for glm objects, but not lm or aov objects. For  
those use, mod$model$B.



On Oct 17, 2005, at 6:26 AM, Martin Henry H. Stevens wrote:

> Hi Jose,
> I am just beginning to plumb the depths of lattice, but perhaps my
> recent experience can help.
> I recently figured out (with encouragement from the list) how to plot
> predicted values from a model into the appropriate panel. I am
> certain that what I have done can be done better, but the following
> appears to work for me.
>
> Imagine the model
> mod <- lm(Y ~ A + B)
> where A is continuous and B is a factor.
>
> I created a new function to use in the panel
>
> panel.modfinal <- function(mod, x, y, subscripts, groups)
>      xfit <- seq(min(x), max(x), length=21)
>      b <- factor( rep(levels(mod$data$B), rep(21,4)) )
>      yfit <- predict(mod, newdata=data.frame(A=rep(xfit,4), B=b) )
> [b==unique(groups[subscripts] ) ]
>      llines(xfit,yfit,lty=1) }
>
> I then plot the data and the fitted lines with constant slope and
> unique intercepts:
>
> xyplot(Y ~ A | B, groups=B,
>              panel=function(x,y, subscripts,groups){
>              panel.xyplot(x,y)
>              panel.modfinal(mod,x,y,subscripts,groups) } ).
>
> "groups" seems to identify a variable that you want pass to a panel
> or legend/key function, and subscripts seems to identify the rows
> used in each panel.
>
> I hope the above is correct and doesn't thereby mislead you, but it
> seems to work for me.
>
> Hank Stevens
>
> On Oct 14, 2005, at 7:34 PM, Jose Claudio Faria wrote:
>
>
>> # Dear R list,
>> #
>> # I'm needing help with lattice, regression and respective lines.
>> # My data is below:
>>
>> bra  = gl(2, 24, label = c('c', 's'))
>> em   = rep(gl(3, 8,  label = c('po', 'pov', 'ce')), 2)
>> tem  = rep(c(0, 0, 30, 30, 60, 60, 90, 90), 6)
>> tem2 = tem^2
>> r    = rep(1:2, 24)
>> y    = c(40.58, 44.85, 32.55, 35.68, 64.86, 51.95, 42.52, 52.21,
>>           40.58, 44.85, 33.46, 46.09, 12.75, 18.01, 16.82, 13.69,
>>           40.58, 44.85, 34.45, 29.89, 34.91, 28.10, 27.52, 22.24,
>>           48.68, 47.25, 45.58, 45.33, 41.03, 51.20, 45.85, 54.45,
>>           48.68, 47.25, 19.88, 19.67, 16.20, 13.49, 13.75, 18.80,
>>           48.68, 47.25, 42.19, 39.91, 34.69, 34.11, 32.74, 34.24)
>>
>> Df = data.frame(bra, em, tem, tem2, r, y)
>>
>> # Regressions
>> attach(Df)
>>    Dfs1=subset(Df, (bra=='s' & em=='pov'), select=c(bra, em, tem,
>> tem2, r, y))
>>    Dfs1
>>    rlin1=lm(y ~ tem + tem2, data=Dfs1)
>>    summary(rlin1)
>>
>>    Dfs2=subset(Df, (bra=='s' & em=='po'), select=c(bra, em, tem, r,
>> y))
>>    Dfs2
>>    rlin2=lm(y ~ tem, data=Dfs2)
>>    summary(rlin2)
>>
>>    Dfs3=subset(Df, (bra=='s' & em=='ce'), select=c(bra, em, tem,
>> tem2, r, y))
>>    Dfs3
>>    rlin3=lm(y ~ tem + tem2, data=Dfs3)
>>    summary(rlin3)
>> detach(Df)
>>
>> # I would like to plot with lattice 'y ~ tem | em',
>> # with the panels ('po', 'pov' and 'ce'),
>> # and the its respective regressions lines:
>> # a) linear for panel 'po' or better, without line;
>> # b) quadratic for 'pov' and 'ce'
>>
>> # Is it possible? Could somebody hel me?
>>
>> # I'm trying:
>> library(lattice)
>> attach(Df)
>>    Dfs=subset(Df, bra=='s', select=c(bra, em, tem, y))
>>    Dfs
>>    xyplot(y ~ tem | em,
>>           data = Dfs, ylim=c(10, 60), xlim=c(-10, 110),
>>           ylab='y', xlab='Time, days',
>>           layout = c(3,1))
>> detach(Df)
>>
>> TIA,
>> -- 
>> Jose Claudio Faria
>> Brasil/Bahia/UESC/DCET
>> Estatistica Experimental/Prof. Adjunto
>> mails:
>>   joseclaudio.faria at terra.com.br
>>   jc_faria at uesc.br
>>   jc_faria at uol.com.br
>> tel: 73-3634.2779
>>
>> ______________________________________________
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>>
>>
>
> Dr. Martin Henry H. Stevens, Assistant Professor
> 338 Pearson Hall
> Botany Department
> Miami University
> Oxford, OH 45056
>
> Office: (513) 529-4206
> Lab: (513) 529-4262
> FAX: (513) 529-4243
> http://www.cas.muohio.edu/~stevenmh/
> http://www.muohio.edu/ecology/
> http://www.muohio.edu/botany/
> "E Pluribus Unum"
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! http://www.R-project.org/posting- 
> guide.html
>

Dr. Martin Henry H. Stevens, Assistant Professor
338 Pearson Hall
Botany Department
Miami University
Oxford, OH 45056

Office: (513) 529-4206
Lab: (513) 529-4262
FAX: (513) 529-4243
http://www.cas.muohio.edu/~stevenmh/
http://www.muohio.edu/ecology/
http://www.muohio.edu/botany/
"E Pluribus Unum"