The mean values theorem of integration (which I think typifies the differences in thinking between mathematicians and statisticians) says that the integral from a to b is equal to the average value of the curve between a and b times the distance from a to b (b - a).
I would be interested in how similar the areas computed using the other methods suggested compare to just averaging your data and multiplying by the distance. -- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare greg.s...@imail.org 801.408.8111 > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r- > project.org] On Behalf Of suse > Sent: Thursday, July 01, 2010 8:57 AM > To: r-help@r-project.org > Subject: [R] Calculate area under a curve > > > Hi, > > I want to know the area under a curve, which is not given as a > function, but > as values in a time series. It is not a smooth curve, but switches > often > between positive values and zero (the values describe the moisture in > the > soil over a year, one entry is one day). I already tried > area.between.curves, but got only 0 as result. I guess, it doesn't work > because of these multiple changes between 0 and positive values (most > of the > time, the values are 0 and in the certain case I tested, the positive > values > were only on single days; but for other values positive values last > longer) > I hope, someone can help me! > > THank you! > -- > View this message in context: http://r.789695.n4.nabble.com/Calculate- > area-under-a-curve-tp2275283p2275283.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. ______________________________________________ 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.
