[R] [FORGED] How to fit the following data and get the equation describing them?
Rolf Turner
r@turner @end|ng |rom @uck|@nd@@c@nz
Wed Feb 13 02:16:12 CET 2019
On 2/13/19 12:33 PM, Martin Beseda wrote:
> Hello everybody,
>
> I have a following data-set:
>
> > data$R
> [1] 0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10 1.15 1.20 1.25
> 1.30 1.35 1.40
> [16] 1.45 1.50 1.55 1.60 1.65 1.70 1.75 1.80 1.85 1.90 1.95 2.00
> 2.05 2.10 2.15
> [31] 2.20 2.25 2.30 2.35 2.40 2.45 2.50 2.60 2.65 2.70 2.75 2.80
> 2.85 2.90 2.95
> [46] 3.00 3.05 3.10 3.15 3.20 3.25 3.30 3.35 3.40 3.45 3.50 3.55
> 3.60 3.65 3.70
> [61] 3.75 3.80 3.85 3.90 3.95 4.00 4.05 4.10 4.15 4.20 4.25 4.30
> 4.35 4.40 4.45
> [76] 4.50 4.55 4.90 4.95
> > data$MRCI8
> [1] 69.10108 56.65276 47.82651 41.64975 37.41315 33.68440 31.29635
> 29.75257
> [9] 28.87221 28.34471 27.71358 26.05035 24.95444 24.03100 23.29969
> 22.71869
> [17] 22.25380 21.87805 21.56874 21.30299 21.01756 20.61259 20.22289
> 19.88496
> [25] 19.59455 19.34637 19.11511 18.94022 18.79525 18.67703 18.58289
> 18.51252
> [33] 18.45438 18.41333 18.38730 18.37395 18.37071 18.38427 18.39670
> 18.41077
> [41] 18.42544 18.44003 18.45415 18.46754 18.48009 18.49176 18.50254
> 18.51246
> [49] 18.52155 18.52988 18.53748 18.54440 18.55068 18.55633 18.56108
> 18.59038
> [57] 18.59568 18.60022 18.60429 18.60789 18.61100 18.61363 18.61581
> 18.61763
> [65] 18.61914 18.62043 18.62155 18.62256 18.62349 18.62436 18.62520
> 18.62602
> [73] 18.62682 18.62761 18.62839 18.62915 18.62990 18.67205 18.67038
>
>
> I need to fit the data and to get the equation describing the line.
>
> 1) I know, I can fit the points using smooth.spline but I have no idea,
> if it's possible to get the equation as y(x) = c_0 + c_1x + c_2x^2.
>
> 2) If it's not possible, then I'd like to fit the data with
> Lennard-Jones potential
> (https://en.wikipedia.org/wiki/Lennard-Jones_potential), i.e. with the
> formula
>
> V(r) = 4e * ( (s/r)^12 - (s/r)^6 ),
>
> where 'e' and 's' are the coefficients to be fitted. I have no idea, if
> it's possible to specify the exact position of fitted coefficients, i.e.
> inside the fraction like here.
>
>
>
> Could you, please, advise me, how to do any of these things?
>
> Thank you very much.
You seem to be way out of your depth. You would be well advised to seek
local help from a qualified statistician.
cheers,
Rolf Turner
--
Honorary Research Fellow
Department of Statistics
University of Auckland
Phone: +64-9-373-7599 ext. 88276
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