[R] Plot for 10 years extrapolation

[Bert Gunter]

Incidentally, if all you wanted to do was plot fitted values, the
predict method is kinda overkill, as it's just the fitted line from
the model. But I assume you wanted to plot CI's/PI's also, as the
example illustrated.

-- Bert

On Thu, Oct 26, 2023 at 1:56 PM Bert Gunter <bgunter.4567 using gmail.com> wrote:
>
> from ?predict.lm:
>
> "predict.lm produces a vector of predictions or a matrix of
> predictions and bounds with column names fit, lwr, and upr if interval
> is set. "
>
> ergo:
> predict(model, dfuture, interval = "prediction")[,"fit"]  ## or [,1]
> as it's the first column in the returned matrix
>
> is your vector of predicted values that you can plot against
> dfuture$date however you would like, e.g. with different colors,
> symbols, or whatever. Exactly how you do this depends on what graphics
> package you are using. The example in ?predict.lm shows you how to do
> it with R's base graphics and overlaying prediction and confidence
> intervals.
>
> Cheers,
> Bert
>
> On Thu, Oct 26, 2023 at 11:27 AM varin sacha via R-help
> <r-help using r-project.org> wrote:
> >
> > Dear R-Experts,
> >
> > Here below my R code working but I don't know how to complete/finish my R code to get the final plot with the extrapolation for the10 more years.
> >
> > Indeed, I try to extrapolate my data with a linear fit over the next 10 years. So I create a date sequence for the next 10 years and store as a dataframe to make the prediction possible.
> > Now, I am trying to get the plot with the actual data (from year 2004 to 2018) and with the 10 more years extrapolation.
> >
> > Thanks for your help.
> >
> > ####################################################
> > date <-as.Date(c("2018-12-31", "2017-12-31", "2016-12-31", "2015-12-31", "2014-12-31", "2013-12-31", "2012-12-31", "2011-12-31", "2010-12-31", "2009-12-31", "2008-12-31", "2007-12-31", "2006-12-31", "2005-12-31", "2004-12-31"))
> >
> > value <-c(15348, 13136, 11733, 10737, 15674, 11098, 13721, 13209, 11099, 10087, 14987, 11098, 13421, 9023, 12098)
> >
> > model <- lm(value~date)
> >
> > plot(value~date ,col="grey",pch=20,cex=1.5,main="Plot")
> > abline(model,col="darkorange",lwd=2)
> >
> > dfuture <- data.frame(date=seq(as.Date("2019-12-31"), by="1 year", length.out=10))
> >
> > predict(model,dfuture,interval="prediction")
> > ########################################################
> >
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