Hello,
I am trying to fit a model to some "death over time" data that does not fit the
criteria for the usual LD50 type models (the counts are too large). I am using
a simple linear model in an attempt to plot a nice line on a scatter plot and
calculate some LD values to use in designing an experiment. Here is the basic
idea of what I'm doing:
head(mort)
Time Density
0 2233333333
0 2100000000
0 1933333333
5 1900000000
5 1433333333
5 900000000
plot(Density~Time)
This plots something that looks a lot like a decay rate
mod<-lm(log(Density)~Time)
xv<-seq(0,60,0.1)
yv<-exp(predict(mod,list(time=xv)))
lines(xv,yv)
Everything seems to work fine until I try to plot the lines, but then I get the
error message:
Error in xy.coords(x, y) : 'x' and 'y' lengths differ
Checking the lengths of x and y confirms that somehow the object yv is not
using xv to predict the data, and is only predicting as many data points as
there are rows in the data frame.
Any ideas on why this might be would be very much appreciated.
Thank you,
Julie
[[alternative HTML version deleted]]
______________________________________________
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.
