Hello to everybody,
I want to implement a non-linear least square curve fitting and I am using
the package "nlmrt", concretely the function nlxb. I have a dataset
with
three variables and 176 values, one response variables (R) and two
predicting variables (T and H). When I fit a model of the form R ~
a*b^((T-10)/10) to my data using the function nlxb seems to be all ok with
a complet output; the same happens when I fit a model R ~ a + b*H - c*H^2.
But due to my research interest, when I try to fit a model result of the
product of the above models (R ~ (b1*b2^((T-10)/10))*(b3 + b4*H - b5*H^2) I
do obtain NA values in the SE, tstat and pval fields from the nlxb output,
as showed below:
nlmrt class object: x
residual sumsquares = 25348 on 176 observations
after 4 Jacobian and 5 function evaluations
name coeff SE tstat pval
gradient JSingval
R10 0.0619936 NA NA NA
7.494e-06 8822
Q10 2.27113 NA NA NA
5.422e-08 217.5
a 133.85 NA NA NA
-2.288e-09 75.96
b 56.8145 NA NA NA
8.058e-09 0.658
c 1.11775 NA NA NA
2.8e-07 1.928e-15
I would like to know which error do you think I am making. Attached is the
document which contain the data.
Thank you very much in advance,
Carlos.
--
Carlos Ortiz O?ate
PhD student
Department of Agricultural Production
Technical University of Madrid
e-mail: ortiz.onate.carlos at gmail.com <teba at life.ku.dk>
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R T H
36.47 14.10 5.95
34.28 14.25 5.65
35.86 14.90 7.78
38.18 18.10 4.53
33.52 14.40 6.15
29.44 14.60 4.55
34.79 14.80 6.78
20.38 16.70 3.58
26.70 14.90 3.00
33.30 14.90 3.65
20.28 15.00 3.58
51.18 16.90 2.78
29.76 14.90 2.48
14.90 15.10 2.40
21.05 15.30 3.10
16.18 17.10 2.85
26.50 11.40 10.85
37.69 11.90 7.08
37.37 11.90 7.30
27.02 12.00 5.83
42.16 7.20 26.03
47.75 7.70 20.15
53.05 7.90 17.78
26.48 8.00 13.53
47.50 7.20 11.45
28.47 7.40 20.85
45.62 7.40 15.23
42.31 7.90 16.45
18.10 4.10 27.35
27.71 5.50 17.58
34.27 5.60 28.33
27.75 5.70 21.03
33.09 4.20 37.28
19.05 4.20 41.63
14.08 4.80 36.48
23.15 5.30 28.93
24.64 4.30 31.48
35.80 4.40 33.50
23.41 4.40 32.63
29.63 4.60 25.25
78.01 10.00 25.45
60.40 10.20 28.28
61.32 10.20 32.35
48.25 10.30 28.45
54.62 11.00 18.63
55.19 11.10 21.18
69.03 11.80 22.03
64.01 14.40 15.78
41.20 12.70 16.43
39.20 12.80 12.63
35.20 12.90 12.88
79.98 15.30 11.03
69.60 13.80 27.65
64.32 14.00 18.20
93.22 14.30 24.58
91.86 15.80 22.23
50.28 14.40 4.73
37.03 14.50 5.03
47.23 14.90 5.33
47.65 16.80 3.93
48.68 14.90 8.38
73.43 14.90 10.00
47.31 15.10 7.38
75.10 15.90 11.93
45.40 12.60 10.13
47.86 12.90 9.28
49.39 13.10 12.05
37.27 13.70 5.53
41.63 8.40 11.43
53.83 9.10 11.48
36.66 9.20 8.85
44.03 9.60 11.23
45.94 5.90 29.70
60.64 6.60 14.98
48.91 6.60 23.83
47.02 6.60 25.13
13.62 1.30 14.98
24.86 1.60 13.75
27.28 1.80 17.08
28.16 2.20 14.13
23.29 2.60 39.65
23.23 2.60 36.35
25.10 2.70 36.05
25.68 3.40 32.85
54.88 9.90 26.80
39.19 10.50 25.23
59.74 10.90 25.03
42.39 12.50 26.23
49.24 6.80 30.65
52.70 7.00 30.00
49.18 7.50 29.43
69.69 7.60 29.30
56.05 9.80 28.78
45.72 9.90 26.53
56.07 10.30 28.70
48.40 11.80 29.25
39.10 14.60 11.15
58.45 14.90 9.58
78.41 15.50 6.50
65.89 15.70 12.05
45.25 13.40 5.40
45.87 14.00 5.00
32.47 14.40 7.05
46.08 16.70 1.65
43.08 16.70 4.18
50.24 17.10 6.43
39.22 17.60 4.83
26.41 17.70 5.30
37.58 12.30 5.78
20.67 12.90 3.15
25.80 12.90 2.63
27.71 13.20 3.80
22.74 13.20 4.50
17.18 13.40 4.50
17.95 13.70 5.75
15.77 14.30 4.75
80.91 6.60 24.25
37.71 6.80 17.00
60.88 7.30 17.50
47.62 7.30 15.00
45.92 4.40 27.50
19.28 5.70 19.50
32.94 6.10 22.25
52.46 6.40 19.50
20.03 1.20 25.88
26.29 1.90 23.75
25.09 2.40 21.00
35.26 2.80 23.10
11.00 1.30 27.60
23.49 1.60 22.70
48.21 2.40 21.38
17.76 3.10 24.95
10.95 1.70 27.60
20.90 1.80 24.95
28.61 1.90 22.70
47.77 2.00 21.38
24.96 3.10 19.55
20.90 6.10 19.75
24.63 6.20 17.45
27.10 6.20 22.30
28.96 10.00 18.70
32.04 10.00 15.80
44.78 10.20 19.60
50.55 10.80 21.40
33.81 11.70 9.80
42.71 12.00 12.60
42.32 12.10 11.90
56.49 16.80 11.20
53.77 12.50 12.10
81.96 12.80 12.00
67.85 13.40 9.00
38.25 13.60 9.90
58.57 16.00 3.40
44.80 16.00 3.40
27.37 16.30 3.00
52.12 18.30 5.10
15.24 13.60 1.70
8.97 13.90 1.80
13.60 14.20 3.90
4.24 14.30 2.60
25.73 13.40 3.80
24.97 13.50 3.10
29.62 13.50 3.90
23.37 13.60 7.10
34.60 10.40 17.60
35.98 10.50 9.70
42.13 10.60 10.60
43.51 11.50 6.80
43.17 8.80 14.60
34.13 9.10 9.80
51.48 9.40 11.00
42.47 9.40 8.30
12.27 6.00 26.30
27.19 6.10 17.20
26.06 6.40 20.70
36.07 6.50 19.90