mtorabi at math.carleton.ca
2010-Aug-30 22:40 UTC
[R] First and second derivatives of raw observations
Dear all, I was asked to send the following question: We have some (raw) observations and would like to get the first and second derivatives in R. Any comment would be appreciated. Thanks, Mahmoud
David Winsemius
2010-Aug-30 22:52 UTC
[R] First and second derivatives of raw observations
On Aug 30, 2010, at 6:40 PM, mtorabi at math.carleton.ca wrote:> Dear all, > > I was asked to send the following question: > > We have some (raw) observations and would like to get the first and > second > derivatives in R. Any comment would be appreciated.From the time of Newton, the quick and dirty (but often very informative) path to first and second derivatives has been via first and second differences. That, of course, assumes that the intervals between these "raw" observation are equal, which might or might not be a sensible assumption given the impossibly vague description of the problem. -- David Winsemius, MD West Hartford, CT
On 30/08/2010 6:40 PM, mtorabi at math.carleton.ca wrote:> Dear all, > > I was asked to send the following question: > > We have some (raw) observations and would like to get the first and second > derivatives in R. Any comment would be appreciated.Fit a model, and take derivatives of the fit. Which model? Depends on the context. Duncan Murdoch