Hi everybody.
I'm just learning to use R. I've got a strange problem and I couldn't find any
answer to my problem. So here am I.
I want to visualize a model of regression on repeated measures :
5 measures (y) by x-value (lx for log10(x) ; lxf colonn is for as.factor) ; 5
x-values.
I fail to use 'abline' command (regression's line don't display) in this
particular context, on a 'stripchart' display. Any idea ?
Here are the few commands that I execute, the lattest being my problem :
> tab <- read.csv2("ex3.csv")
> sapply(tab,data.class)
sujet x xf lx lxf y
"numeric" "numeric" "numeric" "numeric" "numeric" "numeric"
> attach(tab)
> lxf <- as.factor(lxf)
> model1 <- lm(y~lx)
> model2 <- lm(y~lxf)
> model3 <- lm(y~lx+lxf)
> ym <- tapply(y,lxf,mean)
> ym
-0.9 -0.6 -0.3 0 0.3
43.0 60.6 77.2 92.2 109.4
> stripchart(y~lx, method="jitter", jitter=.1, vertical=T, pch=20)
> lines (1:5, ym, type="b", pch=4, cex=2, lty=2)
> abline(model1) ## I don't understand why it doesn't work ; neither do
> abline(coef(model1) or abline(92,45)
## It usually works on any regression, but stripchart maybe is a special plot ;
I suspect an absciss misunderstanding by abline...
Thanks for any help.
I simulated this data set :
lx lxf y
-0,9 -0,9 47
-0,9 -0,9 41
-0,9 -0,9 44
-0,9 -0,9 38
-0,9 -0,9 45
-0,6 -0,6 58
-0,6 -0,6 63
-0,6 -0,6 58
-0,6 -0,6 58
-0,6 -0,6 66
-0,3 -0,3 78
-0,3 -0,3 79
-0,3 -0,3 78
-0,3 -0,3 77
-0,3 -0,3 74
0 0 96
0 0 91
0 0 97
0 0 85
0 0 92
0,3 0,3 109
0,3 0,3 114
0,3 0,3 111
0,3 0,3 104
0,3 0,3 109
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