I have a data set of 6 or so ordered pairs, and I've been able to graph
them and have decided to use a high-order polynomial regression. I've
used the following piece of code:
regression <- function(x,y) {
x <- c(insert_numbers_here)
y <- c(insert_other_numbers_here)
fit <- lm(y ~ x + I(x^2) + I(x^3) + I(x^4) + I(x^5) + I(x^6) +
I(x^7) + I(x^8) + I(x^9))
summary(fit)
This gives me the coefficients for the regression very nicely, but I
would like to plot both the data and the regression curve together. How
do I plot that regression curve as a function, and can I put it on the
same set of axes as my data scatter plot?
Thanks in advance for your help!
-KE
Hi Ken, Perhaps something like plot(x,y) lines(sort(x), fit$fitted.values[order(x)]) should do what I think you want. I think you have to be a bit careful on the ordering of the fitted values so that they match up with the order of the x variable, otherwise you get an odd looking line plot. Regards, Andrew On Oct 28, 5:42?am, Ken Ervin <ervinj... at gmail.com> wrote:> I have a data set of 6 or so ordered pairs, and I've been able to graph > them and have decided to use a high-order polynomial regression. ?I've > used the following piece of code: > > regression <- function(x,y) { > ? ? x <- c(insert_numbers_here) > ? ? y <- c(insert_other_numbers_here) > ? ? fit <- lm(y ~ x + I(x^2) + I(x^3) + I(x^4) + I(x^5) + I(x^6) + > I(x^7) + I(x^8) + I(x^9)) > ? ? summary(fit) > > This gives me the coefficients for the regression very nicely, but I > would like to plot both the data and the regression curve together. ?How > do I plot that regression curve as a function, and can I put it on the > same set of axes as my data scatter plot? > > Thanks in advance for your help! > > -KE > > ______________________________________________ > R-h... at r-project.org mailing listhttps://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guidehttp://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code.
Ken Ervin wrote:> I have a data set of 6 or so ordered pairs, and I've been able to graph > them and have decided to use a high-order polynomial regression. I've > used the following piece of code: > > regression <- function(x,y) { > x <- c(insert_numbers_here) > y <- c(insert_other_numbers_here) > fit <- lm(y ~ x + I(x^2) + I(x^3) + I(x^4) + I(x^5) + I(x^6) + I(x^7) > + I(x^8) + I(x^9)) > summary(fit) > > This gives me the coefficients for the regression very nicely, but I > would like to plot both the data and the regression curve together. How > do I plot that regression curve as a function, and can I put it on the > same set of axes as my data scatter plot? >Are you sure that fitting such a high-degree polynomial makes sense? Is there any theory to support the model? If you really want to do this, then use predict.lm(): ## with xmin, xmax as the limits of your scatterplot xx <- seq(xmin, xmax, length=51) yy <- predict(fit, newdata=list(x=xx)) lines(xx, yy) ## add to scatterplot -Peter Ehlers> Thanks in advance for your help! > > -KE > > ______________________________________________ > R-help at 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. > >
?curve regards, Tom Ken Ervin schrieb:> I have a data set of 6 or so ordered pairs, and I've been able to graph > them and have decided to use a high-order polynomial regression. I've > used the following piece of code: > > regression <- function(x,y) { > x <- c(insert_numbers_here) > y <- c(insert_other_numbers_here) > fit <- lm(y ~ x + I(x^2) + I(x^3) + I(x^4) + I(x^5) + I(x^6) + I(x^7) > + I(x^8) + I(x^9)) > summary(fit) > > This gives me the coefficients for the regression very nicely, but I > would like to plot both the data and the regression curve together. How > do I plot that regression curve as a function, and can I put it on the > same set of axes as my data scatter plot? > > Thanks in advance for your help! > > -KE > > ______________________________________________ > R-help at 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.