On Apr 6, 2010, at 12:13 PM, marta rufino wrote:
ok, not really sorted :-(does not work in other values,...and I am
not really sure how to come over it
x=c(0.0191,0.0088,0.0150,0.0105,0.0430,0.0697,0.1999)
y=c(58,107,152,239,362,512,724)
x1=0.02220172
kk=y[x==min(x)]
approxExtrap(x[y>kk],y[y>kk],x1, method="linear")
approx(x[y>kk],y[y>kk],x1)
plot(x, y, typ="o")
abline(v=x1, col=8)
abline(h=approx(x[y>kk],y[y>kk],x1), col=6)
Once again, I wanted to get the upper value, the one close to 300
and not the lowest or middle :-(
Any ideia how to get that? I tried looking inside the code of
approx, but it is in .C
I am not finding your request to be very clear. You use the term
extrapolation but what you are requesting is interior to the range of
the x values, so it's not really extrapolation. Do you want an
estimate based on a linear fit to the data?
plot(x,y)
lines(x, predict(lm(y ~ x) )
points(0.02220172 , predict(lm(y ~ x),
newdata=data.frame(x=0.02220172)), col="red", cex=3)
Thank you once again,
All the best,
Marta
David Winsemius, MD
West Hartford, CT
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