[Rd] problem with abine(lm(...)) for plot(y~x, log='xy')

Spencer Graves spencer.graves at prodsyse.com
Sun Aug 7 21:03:55 CEST 2016


        In the following plot, the fitted line plots 100 percent above 
the points:

tstDat <- data.frame(x=10^(1:3), y=10^(1:3+.1*rnorm(3)))
tstFit <- lm(log(y)~log(x), tstDat)
plot(y~x, tstDat, log='xy')

        I can get the correct line with the following:

tstPredDat <- data.frame(x=10^seq(1, 3, len=2))
tstPred <- predict(tstFit, tstPredDat)
lines(tstPredDat$x, exp(tstPred))

        I tried "abline(tstFit)" hoping it would work.  If the error had 
not been so obvious, I might not have noticed it.

        Thanks for your work to build a better R (and through that a 
better world).

        Spencer Graves

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