I am trying to plot the logistic regression of a dataset (# of living flies vs days the flies are alive) and then fit a best-fit line to this data.
Here is my code: plot(fflies$living~fflies$day,xlab="Number of Days",ylab="Number of Fruit Flies",main="Number of Living Fruit Flies vs Day",pch=16) alive <- (fflies$living) dead <- (fflies$living[1]-alive) glm.fit <- glm(cbind(alive,dead)~fflies$day,family="binomial") summary(glm.fit) lines(sort(fflies$day),fitted(glm.fit) [order (fflies$day)],col = "red",lwd=2) lines(glm.fit,col = "red",lwd=2) My problem is that, while I am pretty sure that I did the 'glm' command correctly, when I try to plot this as a best-fit line on my data, it does not fit (clearly on a different scale somehow). Can anyone enlighten me about what I am doing wrong? Should I be scaling one of these somehow? I've tried various types of scaling but nothing plots the line on top of the plot (no matter which I scale). Thanks so much for whatever help you can give me! Cheers, Melissa -- View this message in context: http://r.789695.n4.nabble.com/logistic-regression-tp4530651p4530651.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
