J'ai un problème avec la somme des résidus carrés d'un raccord. La somme carrée des résidus est trop élevée, ce qui indique que l'ajustement n'est pas très bon. Cependant, visuellement, ça a l'air d'avoir cette valeur résiduelle très élevée ... Quelqu'un peut-il m'aider à savoir ce qui se passe?Somme résiduelle très élevée
Mes données:
x=c(0.017359, 0.019206, 0.020619, 0.021022, 0.021793, 0.022366, 0.025691, 0.025780, 0.026355, 0.028858, 0.029766, 0.029967, 0.030241, 0.032216, 0.033657,
0.036250, 0.039145, 0.040682, 0.042334, 0.043747, 0.044165, 0.044630, 0.046045, 0.048138, 0.050813, 0.050955, 0.051910, 0.053042, 0.054853, 0.056886,
0.058651, 0.059472, 0.063770,0.064567, 0.067415, 0.067802, 0.068995, 0.070742,0.073486, 0.074085 ,0.074452, 0.075224, 0.075853, 0.076192, 0.077002,
0.078273, 0.079376, 0.083269, 0.085902, 0.087619, 0.089867, 0.092606, 0.095944, 0.096327, 0.097019, 0.098444, 0.098868, 0.098874, 0.102027, 0.103296,
0.107682, 0.108392, 0.108719, 0.109184, 0.109623, 0.118844, 0.124023, 0.124244, 0.129600, 0.130892, 0.136721, 0.137456, 0.147343, 0.149027, 0.152818,
0.155706,0.157650, 0.161060, 0.162594, 0.162950, 0.165031, 0.165408, 0.166680, 0.167727, 0.172882, 0.173264, 0.174552,0.176073, 0.185649, 0.194492,
0.196429, 0.200050, 0.208890, 0.209826, 0.213685, 0.219189, 0.221417, 0.222662, 0.230860, 0.234654, 0.235211, 0.241819, 0.247527, 0.251528, 0.253664,
0.256740, 0.261723, 0.274585, 0.278340, 0.281521, 0.282332, 0.286166, 0.288103, 0.292959, 0.295201, 0.309456, 0.312158, 0.314132, 0.319906, 0.319924,
0.322073, 0.325427, 0.328132, 0.333029, 0.334915, 0.342098, 0.345899, 0.345936, 0.350355, 0.355015, 0.355123, 0.356335, 0.364257, 0.371180, 0.375171,
0.377743, 0.383944, 0.388606, 0.390111, 0.395080, 0.398209, 0.409784, 0.410324, 0.424782)
y= c(34843.40, 30362.66, 27991.80 ,28511.38, 28004.74, 27987.13, 22272.41, 23171.71, 23180.03, 20173.79, 19751.84, 20266.26, 20666.72, 18884.42, 17920.78, 15980.99, 14161.08, 13534.40, 12889.18, 12436.11,
12560.56, 12651.65, 12216.11, 11479.18, 10573.22, 10783.99, 10650.71, 10449.87, 10003.68, 9517.94, 9157.04, 9104.01, 8090.20, 8059.60, 7547.20, 7613.51, 7499.47, 7273.46, 6870.20, 6887.01,
6945.55, 6927.43, 6934.73, 6993.73, 6965.39, 6855.37, 6777.16, 6259.28, 5976.27, 5835.58, 5633.88, 5387.19, 5094.94, 5129.89, 5131.42, 5056.08, 5084.47, 5155.40, 4909.01, 4854.71,
4527.62, 4528.10, 4560.14, 4580.10, 4601.70, 3964.90, 3686.20, 3718.46, 3459.13, 3432.05, 3183.09, 3186.18, 2805.15, 2773.65, 2667.73, 2598.55, 2563.02, 2482.63, 2462.49, 2478.10,
2441.70, 2456.16, 2444.00, 2438.47, 2318.64, 2331.75, 2320.43, 2303.10, 2091.95, 1924.55, 1904.91, 1854.07, 1716.52, 1717.12, 1671.00, 1602.70, 1584.89, 1581.34, 1484.16, 1449.26,
1455.06, 1388.60, 1336.71, 1305.60, 1294.58, 1274.36, 1236.51, 1132.67, 1111.35, 1095.21, 1097.71, 1077.05, 1071.04, 1043.99, 1036.22, 950.26, 941.06, 936.37, 909.72, 916.45,
911.01, 898.94, 890.68, 870.99, 867.45, 837.39, 824.93, 830.61, 815.49, 799.77, 804.84, 804.88, 775.53, 751.95, 741.01, 735.86, 717.03, 704.57, 703.74, 690.63,
684.24, 650.30, 652.74, 612.95)
Ensuite, faire entrer en utilisant la fonction nlsLM (package minpack.lm):
library(magicaxis)
library(minpack.lm)
sig.backg=3*10^(-3)
mod <- nlsLM(y ~ a *(1 + (x/b)^2)^c+sig.backg,
start = c(a = 0, b = 1, c = 0),
trace = TRUE)
## plot data
magplot(x, y, main = "data", log = "xy", pch=16)
## plot fitted values
lines(x, fitted(mod), col = 2, lwd = 4)
Cette valeur est le résidu:
> print(mod)
Nonlinear regression model
model: y ~ a * (1 + (x/b)^2)^c + sig.backg
data: parent.frame()
a b c
68504.2013 0.0122 -0.6324
residual sum-of-squares: 12641435
Number of iterations to convergence: 34
Achieved convergence tolerance: 0.0000000149
La somme des carrés résiduels est trop élevée: 12641435 ...
Est-ce exact ou quelque chose ne va pas avec le réglage? C'est mauvais?
"trop élevé" sans validation quantitative est assez trompeur –