Oh,yes, I found out this according to your reply.Thanks.
As to time series analysis, in order to show the effect of smoothing or filtering,the common command is: plot(ts0); lines(fitted(...)) But not "lines(fitted(...) ~ time(ts) )" How to understand this then? Many thanks. Best. At 2013-09-18 08:49:51,"Duncan Murdoch" <murdoch.dun...@gmail.com> wrote: >On 13-09-17 6:36 PM, meng wrote: >> Thanks for your reply. >> >> Is "fitted(lm(...))" the same as "values" of lines(values)? >> >> If yes,then why the range of lines(values) is different from >> range(fitted(lm(...)))? > >You are plotting against the wrong x axis, and you don't see all the values. > >Duncan Murdoch > >> If no, what "values" refers to? >> >> >> >> At 2013-09-17 20:56:04,"Duncan Murdoch" <murdoch.dun...@gmail.com> wrote: >>>On 13-09-17 8:06 AM, meng wrote: >>>> Hi all: >>>> I met a question about "lines". >>>> >>>> >>>> attach(cars) >>>> >>>> >>>> plot(dist ~ speed) >>>> #add the regression line to the plot >>>> lines(fitted(lm(dist~speed)) ~ speed) >>>> >>>> >>>> plot(dist ~ speed) >>>> #what kind of curve does the following command add to the plot? >>>> lines(fitted(lm(dist~speed))) >>>> >>>> >>>> My question is : >>>> what kind of curve does the last command add to the plot? >>> >>>Look at the class of fitted(lm(...)). It is "numeric". So what you're >>>seeing is the same as if you computed the fitted values, and then did >>> >>>lines(values) >>> >>>Since values is just a vector of numbers, that will plot them as y >>>values against x values 1:length(values). That's unlikely to be a >>>useful thing to do. >>> >>>Duncan Murdoch >>> >>>> >>>> >>>> My guess:maybe the level of fitted values? >>>>> range(fitted(lm(dist~speed))) >>>> [1] -1.84946 80.73112 >>>> >>>> >>>> But from the plot,I can see the range of the curve is about 10 to 40 more >>>> or less,which is different from(-1.84946, 80.73112).So the curve must not >>>> be the fitted values.What kind of curve does the last command add to the >>>> plot then? >>>> >>>> >>>> >>>> >>>> Many thanks for your help >>>> >>>> >>>> My best >>>> [[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. >>>> >>> >> >> >> > [[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.
