Ejercicio de Prueba de Normalidad

library(wooldridge)
## Warning: package 'wooldridge' was built under R version 4.4.3
data("hprice1")
head(force(hprice1), n=5)
##   price assess bdrms lotsize sqrft colonial   lprice  lassess llotsize   lsqrft
## 1   300  349.1     4    6126  2438        1 5.703783 5.855359 8.720297 7.798934
## 2   370  351.5     3    9903  2076        1 5.913503 5.862210 9.200593 7.638198
## 3   191  217.7     3    5200  1374        0 5.252274 5.383118 8.556414 7.225482
## 4   195  231.8     3    4600  1448        1 5.273000 5.445875 8.433811 7.277938
## 5   373  319.1     4    6095  2514        1 5.921578 5.765504 8.715224 7.829630
# Mostrar las primeras 5 observaciones

Estimar el modelo

library(stargazer)
modelo_estimado <- lm(formula =price~lotsize+sqrft+bdrms, data = hprice1)
stargazer(modelo_estimado, title = "Modelo estimado", type = "text")
## 
## Modelo estimado
## ===============================================
##                         Dependent variable:    
##                     ---------------------------
##                                price           
## -----------------------------------------------
## lotsize                      0.002***          
##                               (0.001)          
##                                                
## sqrft                        0.123***          
##                               (0.013)          
##                                                
## bdrms                         13.853           
##                               (9.010)          
##                                                
## Constant                      -21.770          
##                              (29.475)          
##                                                
## -----------------------------------------------
## Observations                    88             
## R2                             0.672           
## Adjusted R2                    0.661           
## Residual Std. Error      59.833 (df = 84)      
## F Statistic           57.460*** (df = 3; 84)   
## ===============================================
## Note:               *p<0.1; **p<0.05; ***p<0.01

1. Estime el siguiente modelo,price = ˆα + ˆα1(lotsize) + ˆα2(sqrft) + ˆα3(bdrms) +∈

library(tseries)
salida_jb <- jarque.bera.test(modelo_estimado$residuals)
salida_jb
## 
##  Jarque Bera Test
## 
## data:  modelo_estimado$residuals
## X-squared = 32.278, df = 2, p-value = 9.794e-08
# Librerías necesarias
library(tseries)
library(fastGraph)

# Obtener residuos del modelo
residuos <- residuals(modelo_estimado)

# Realizar la prueba de Jarque-Bera
salida_JB <- jarque.bera.test(residuos)

# Parámetros para la gráfica
alpha_sig <- 0.05
JB <- salida_JB$statistic
gl <- salida_JB$parameter
VC <- qchisq(1 - alpha_sig, gl, lower.tail = TRUE)

# Gráfica de la región crítica
shadeDist(JB,
          ddist = "dchisq",
          parm1 = gl,
          lower.tail = FALSE,
          xmin = 0,
          sub = paste("VC:", round(VC, 2), " ", "JB:", round(JB, 2)))

Usando normtest

library(tseries)
salida_jb <- jarque.bera.test(modelo_estimado$residuals)
salida_jb
## 
##  Jarque Bera Test
## 
## data:  modelo_estimado$residuals
## X-squared = 32.278, df = 2, p-value = 9.794e-08

Prueba de Kolmogorov Smirnov

library(dplyr)
library(gt)
library(gtExtras)
residuos<-modelo_estimado$residuals  
residuos %>%  
  as_tibble() %>%  
  mutate(posicion=row_number()) %>%  
  arrange(value) %>%  
  mutate(dist1=row_number()/n()) %>%  
  mutate(dist2=(row_number()-1)/n()) %>%  
  mutate(zi=as.vector(scale(value,center=TRUE))) %>%  
  mutate(pi=pnorm(zi,lower.tail = TRUE)) %>%  
  mutate(dif1=abs(dist1-pi)) %>%  
  mutate(dif2=abs(dist2-pi)) %>%  
  rename(residuales=value) -> tabla_KS  


 tabla_KS %>%  
  gt() %>%  
  tab_header("Tabla para calcular el Estadistico KS") %>%  
  tab_source_note(source_note = "Fuente: Elaboración propia") %>%  
  tab_style(  
    style = list(
      cell_fill(color = "#A569BD"),  
      cell_text(style = "italic")  
      ),
    locations = cells_body(  
      columns = dif1,  
      rows = dif1==max(dif1)  
    )) %>%
   tab_style(  
    style = list(
      cell_fill(color = "#3498DB"),  
      cell_text(style = "italic")  
      ),
    locations = cells_body(  
      columns = dif2,  
      rows = dif2==max(dif2)  
    ))
Tabla para calcular el Estadistico KS
residuales posicion dist1 dist2 zi pi dif1 dif2
-120.026447 81 0.01136364 0.00000000 -2.041515459 0.02059981 0.0092361731 0.0205998094
-115.508697 77 0.02272727 0.01136364 -1.964673586 0.02472601 0.0019987418 0.0133623781
-107.080889 24 0.03409091 0.02272727 -1.821326006 0.03427866 0.0001877487 0.0115513850
-91.243980 48 0.04545455 0.03409091 -1.551957925 0.06033615 0.0148816002 0.0262452366
-85.461169 12 0.05681818 0.04545455 -1.453598781 0.07302879 0.0162106057 0.0275742421
-77.172687 32 0.06818182 0.05681818 -1.312620980 0.09465535 0.0264735301 0.0378371665
-74.702719 54 0.07954545 0.06818182 -1.270609602 0.10193378 0.0223883300 0.0337519664
-65.502849 39 0.09090909 0.07954545 -1.114130117 0.13261169 0.0417025941 0.0530662305
-63.699108 69 0.10227273 0.09090909 -1.083450505 0.13930425 0.0370315271 0.0483951634
-62.566594 83 0.11363636 0.10227273 -1.064187703 0.14362184 0.0299854747 0.0413491110
-59.845223 36 0.12500000 0.11363636 -1.017900230 0.15436269 0.0293626861 0.0407263225
-54.466158 13 0.13636364 0.12500000 -0.926408352 0.17711690 0.0407532663 0.0521169027
-54.300415 14 0.14772727 0.13636364 -0.923589260 0.17785010 0.0301228311 0.0414864675
-52.129801 15 0.15909091 0.14772727 -0.886669532 0.18762842 0.0285375141 0.0399011505
-51.441108 17 0.17045455 0.15909091 -0.874955638 0.19079902 0.0203444766 0.0317081129
-48.704980 47 0.18181818 0.17045455 -0.828417174 0.20371714 0.0218989601 0.0332625965
-48.350295 29 0.19318182 0.18181818 -0.822384375 0.20542908 0.0122472664 0.0236109028
-47.855859 11 0.20454545 0.19318182 -0.813974573 0.20782976 0.0032843043 0.0146479407
-45.639765 1 0.21590909 0.20454545 -0.776281294 0.21879146 0.0028823668 0.0142460032
-43.142550 9 0.22727273 0.21590909 -0.733806463 0.23153335 0.0042606233 0.0156242596
-41.749618 57 0.23863636 0.22727273 -0.710114247 0.23881665 0.0001802823 0.0115439187
-40.869022 27 0.25000000 0.23863636 -0.695136302 0.24348494 0.0065150566 0.0048485798
-37.749811 34 0.26136364 0.25000000 -0.642082009 0.26040997 0.0009536682 0.0104099682
-36.663785 71 0.27272727 0.26136364 -0.623609925 0.26644190 0.0062853771 0.0050782592
-36.646568 79 0.28409091 0.27272727 -0.623317083 0.26653809 0.0175528221 0.0061891857
-33.801248 37 0.29545455 0.28409091 -0.574921384 0.28267223 0.0127823120 0.0014186757
-29.766931 16 0.30681818 0.29545455 -0.506302171 0.30632227 0.0004959124 0.0108677240
-26.696234 22 0.31818182 0.30681818 -0.454073044 0.32488813 0.0067063089 0.0180699452
-24.271531 23 0.32954545 0.31818182 -0.412831567 0.33986501 0.0103195566 0.0216831929
-23.651448 86 0.34090909 0.32954545 -0.402284648 0.34373728 0.0028281851 0.0141918214
-19.683427 88 0.35227273 0.34090909 -0.334793052 0.36889060 0.0166178738 0.0279815102
-17.817835 10 0.36363636 0.35227273 -0.303061413 0.38092153 0.0172851663 0.0286488027
-16.762094 60 0.37500000 0.36363636 -0.285104441 0.38778206 0.0127820638 0.0241457002
-16.596960 21 0.38636364 0.37500000 -0.282295711 0.38885839 0.0024947507 0.0138583870
-16.271207 58 0.39772727 0.38636364 -0.276755010 0.39098411 0.0067431583 0.0046204781
-13.815798 56 0.40909091 0.39772727 -0.234991254 0.40710776 0.0019831485 0.0093804879
-13.462160 75 0.42045455 0.40909091 -0.228976273 0.40944368 0.0110108666 0.0003527698
-12.081520 4 0.43181818 0.42045455 -0.205493119 0.41859344 0.0132247451 0.0018611087
-11.629207 51 0.44318182 0.43181818 -0.197799788 0.42160086 0.0215809622 0.0102173258
-11.312669 74 0.45454545 0.44318182 -0.192415834 0.42370825 0.0308372092 0.0194735728
-8.236558 3 0.46590909 0.45454545 -0.140094626 0.44429261 0.0216164775 0.0102528411
-7.662789 70 0.47727273 0.46590909 -0.130335452 0.44815052 0.0291222111 0.0177585748
-6.752801 67 0.48863636 0.47727273 -0.114857588 0.45427900 0.0343573625 0.0229937262
-6.707262 31 0.50000000 0.48863636 -0.114083016 0.45458599 0.0454140074 0.0340503710
-6.402439 85 0.51136364 0.50000000 -0.108898313 0.45664157 0.0547220642 0.0433584278
-5.446904 82 0.52272727 0.51136364 -0.092645733 0.46309251 0.0596347676 0.0482711313
-3.537785 43 0.53409091 0.52272727 -0.060173762 0.47600862 0.0580822876 0.0467186512
-2.824941 61 0.54545455 0.53409091 -0.048049090 0.48083856 0.0646159857 0.0532523493
-2.745208 68 0.55681818 0.54545455 -0.046692922 0.48137899 0.0754391961 0.0640755598
-0.195089 65 0.56818182 0.55681818 -0.003318245 0.49867621 0.0695056040 0.0581419676
1.399296 55 0.57954545 0.56818182 0.023800450 0.50949411 0.0700513452 0.0586877088
5.363331 26 0.59090909 0.57954545 0.091224254 0.53634280 0.0545662924 0.0432026561
6.700640 53 0.60227273 0.59090909 0.113970383 0.54536936 0.0569033628 0.0455397265
7.386314 80 0.61363636 0.60227273 0.125632935 0.54998875 0.0636476093 0.0522839730
9.099900 41 0.62500000 0.61363636 0.154779103 0.56150227 0.0634977329 0.0521340965
12.433611 46 0.63636364 0.62500000 0.211481796 0.58374433 0.0526193043 0.0412556680
16.718018 62 0.64772727 0.63636364 0.284354766 0.61193074 0.0357965328 0.0244328965
18.093192 5 0.65909091 0.64772727 0.307744934 0.62086179 0.0382291219 0.0268654856
18.801816 38 0.67045455 0.65909091 0.319797835 0.62543921 0.0450153400 0.0336517036
19.168108 33 0.68181818 0.67045455 0.326028052 0.62779843 0.0540197476 0.0426561112
19.219211 72 0.69318182 0.68181818 0.326897255 0.62812720 0.0650546167 0.0536909803
20.334434 59 0.70454545 0.69318182 0.345865960 0.63527827 0.0692671805 0.0579035442
24.909926 78 0.71590909 0.70454545 0.423689939 0.66410402 0.0518050676 0.0404414312
26.236229 40 0.72727273 0.71590909 0.446248874 0.67229126 0.0549814685 0.0436178321
30.924022 25 0.73863636 0.72727273 0.525982978 0.70054998 0.0380863808 0.0267227444
32.253952 45 0.75000000 0.73863636 0.548603608 0.70836125 0.0416387548 0.0302751184
32.529367 49 0.76136364 0.75000000 0.553288104 0.70996693 0.0513967091 0.0400330727
32.675968 18 0.77272727 0.76136364 0.555781630 0.71081993 0.0619073452 0.0505437088
33.275839 20 0.78409091 0.77272727 0.565984762 0.71429793 0.0697929786 0.0584293423
36.031430 52 0.79545455 0.78409091 0.612854281 0.73001365 0.0654408934 0.0540772571
37.147186 84 0.80681818 0.79545455 0.631832029 0.73625168 0.0705665028 0.0592028664
40.320875 7 0.81818182 0.80681818 0.685812928 0.75358446 0.0645973596 0.0532337232
44.334467 30 0.82954545 0.81818182 0.754079634 0.77459930 0.0549461574 0.0435825211
46.907165 28 0.84090909 0.82954545 0.797838357 0.78751785 0.0533912405 0.0420276041
54.418366 87 0.85227273 0.84090909 0.925595465 0.82267187 0.0296008528 0.0182372164
55.091131 35 0.86363636 0.85227273 0.937038450 0.82563061 0.0380057535 0.0266421172
55.470305 44 0.87500000 0.86363636 0.943487765 0.82728426 0.0477157353 0.0363520989
62.939597 6 0.88636364 0.87500000 1.070532059 0.85781006 0.0285535797 0.0171899433
66.478628 50 0.89772727 0.88636364 1.130727018 0.87091500 0.0268122757 0.0154486394
67.426518 63 0.90909091 0.89772727 1.146849569 0.87427810 0.0348128083 0.0234491719
67.603959 19 0.92045455 0.90909091 1.149867648 0.87490081 0.0455537393 0.0341901029
69.707122 64 0.93181818 0.92045455 1.185640095 0.88211777 0.0497004123 0.0383367759
69.843246 8 0.94318182 0.93181818 1.187955411 0.88257451 0.0606073068 0.0492436705
74.848732 2 0.95454545 0.94318182 1.273093116 0.89850750 0.0560379553 0.0446743189
112.729191 66 0.96590909 0.95454545 1.917397313 0.97240626 0.0064971714 0.0178608078
163.795081 73 0.97727273 0.96590909 2.785970904 0.99733162 0.0200588896 0.0314225260
198.660139 42 0.98863636 0.97727273 3.378986513 0.99963623 0.0109998685 0.0223635048
209.375830 76 1.00000000 0.98863636 3.561248407 0.99981545 0.0001845478 0.0111790885
Fuente: Elaboración propia

Calculo del estadístico D

D <- max(max(tabla_KS$dif1),max(tabla_KS$dif2))
print(D)
## [1] 0.0754392
matriz_X <- model.matrix(modelo_estimado)
n <- nrow(matriz_X)
print(n)
## [1] 88

Dado que el tamaño de la muestra es mayor a 50, se procede al cálculo del valor crítico. Al aplicar la fórmula correspondiente, se obtiene un valor crítico de 0.875897.

n_KS <- 88
resultado_ks <- 0.855897/sqrt(n_KS)
print(resultado_ks)
## [1] 0.09123893

Conclusión: Como el valor p (0.0754392) es menor que el nivel de significancia establecido (0.09123893), no se rechaza la hipótesis nula. Por lo tanto, se considera que los residuos siguen una distribución normal N(0, σ²).

Usando nortest

library(nortest)
prueba_KS <- lillie.test(modelo_estimado$residuals)
prueba_KS
## 
##  Lilliefors (Kolmogorov-Smirnov) normality test
## 
## data:  modelo_estimado$residuals
## D = 0.075439, p-value = 0.2496

Como el valor p (0.2496) es mayor que el nivel de significancia (0.05), no se rechaza la hipótesis nula. Por lo tanto, se puede asumir que los residuos siguen una distribución normal N(0, σ²).

c) prueba de Shapiro Wilk

cálculo manual

library(dplyr)
library(gt)
residuos<-modelo_estimado$residuals
residuos %>%  
  as_tibble() %>%
  rename(residuales=value) %>%
  arrange(residuales) %>%
  mutate(pi=(row_number()-0.375)/(n()+0.25)) %>%
  mutate(mi=qnorm(pi,lower.tail = TRUE)) %>% 
  mutate(ai=0)->tabla_SW

m<-sum(tabla_SW$mi^2)
n_SW<-nrow(hprice1)
theta<-1/sqrt(n)
tabla_SW$ai[n]<- -2.706056*theta^5+4.434685*theta^4-2.071190*theta^3-0.147981*theta^2+0.2211570*theta+tabla_SW$mi[n]/sqrt(m)
tabla_SW$ai[n-1]<- -3.582633*theta^5+5.682633*theta^4-1.752461*theta^3-0.293762*theta^2+0.042981*theta+tabla_SW$mi[n-1]/sqrt(m)
tabla_SW$ai[1]<- -tabla_SW$ai[n]
tabla_SW$ai[2]<- -tabla_SW$ai[n-1]
omega<-(m-2*tabla_SW$mi[n]^2-2*tabla_SW$mi[n-1]^2)/(1-2*tabla_SW$ai[n]^2-2*tabla_SW$ai[n-1]^2)
tabla_SW$ai[3:(n-2)]<-tabla_SW$mi[3:(n-2)]/sqrt(omega)

tabla_SW %>% 
  mutate(ai_ui=ai*residuales,ui2=residuales^2) ->tabla_SW

tabla_SW %>%
  gt() %>% tab_header("Tabla para calcular el Estadistico W") %>%  
  tab_source_note(source_note = "Fuente: Elaboración propia")
Tabla para calcular el Estadistico W
residuales pi mi ai ai_ui ui2
-120.026447 0.007082153 -2.45306927 -0.286093929 34.338837782 1.440635e+04
-115.508697 0.018413598 -2.08767462 -0.226331231 26.143225495 1.334226e+04
-107.080889 0.029745042 -1.88455395 -0.201511408 21.578020632 1.146632e+04
-91.243980 0.041076487 -1.73832835 -0.185875811 16.960048752 8.325464e+03
-85.461169 0.052407932 -1.62194155 -0.173430814 14.821600075 7.303611e+03
-77.172687 0.063739377 -1.52411994 -0.162970954 12.576906330 5.955624e+03
-74.702719 0.075070822 -1.43903134 -0.153872609 11.494702279 5.580496e+03
-65.502849 0.086402266 -1.36324747 -0.145769197 9.548297773 4.290623e+03
-63.699108 0.097733711 -1.29457343 -0.138426027 8.817614500 4.057576e+03
-62.566594 0.109065156 -1.23151500 -0.131683320 8.238976839 3.914579e+03
-59.845223 0.120396601 -1.17300649 -0.125427129 7.506214499 3.581451e+03
-54.466158 0.131728045 -1.11825971 -0.119573169 6.512691096 2.966562e+03
-54.300415 0.143059490 -1.06667420 -0.114057239 6.193355472 2.948535e+03
-52.129801 0.154390935 -1.01778137 -0.108829231 5.673246083 2.717516e+03
-51.441108 0.165722380 -0.97120790 -0.103849228 5.342119306 2.646188e+03
-48.704980 0.177053824 -0.92665123 -0.099084876 4.825926905 2.372175e+03
-48.350295 0.188385269 -0.88386232 -0.094509548 4.569564512 2.337751e+03
-47.855859 0.199716714 -0.84263354 -0.090101040 4.311862673 2.290183e+03
-45.639765 0.211048159 -0.80278966 -0.085840618 3.917745629 2.082988e+03
-43.142550 0.222379603 -0.76418130 -0.081712307 3.525277277 1.861280e+03
-41.749618 0.233711048 -0.72667986 -0.077702356 3.244043648 1.743031e+03
-40.869022 0.245042493 -0.69017366 -0.073798824 3.016085791 1.670277e+03
-37.749811 0.256373938 -0.65456498 -0.069991263 2.642156946 1.425048e+03
-36.663785 0.267705382 -0.61976766 -0.066270458 2.429725818 1.344233e+03
-36.646568 0.279036827 -0.58570518 -0.062628228 2.295109622 1.342971e+03
-33.801248 0.290368272 -0.55230918 -0.059057264 1.996209250 1.142524e+03
-29.766931 0.301699717 -0.51951819 -0.055550992 1.653582575 8.860702e+02
-26.696234 0.313031161 -0.48727661 -0.052103467 1.390966354 7.126889e+02
-24.271531 0.324362606 -0.45553386 -0.048709282 1.182248861 5.891072e+02
-23.651448 0.335694051 -0.42424369 -0.045363489 1.072912217 5.593910e+02
-19.683427 0.347025496 -0.39336354 -0.042061540 0.827915257 3.874373e+02
-17.817835 0.358356941 -0.36285409 -0.038799229 0.691318234 3.174752e+02
-16.762094 0.369688385 -0.33267878 -0.035572645 0.596272007 2.809678e+02
-16.596960 0.381019830 -0.30280344 -0.032378138 0.537378676 2.754591e+02
-16.271207 0.392351275 -0.27319601 -0.029212277 0.475319006 2.647522e+02
-13.815798 0.403682720 -0.24382619 -0.026071824 0.360203050 1.908763e+02
-13.462160 0.415014164 -0.21466524 -0.022953704 0.309006447 1.812298e+02
-12.081520 0.426345609 -0.18568573 -0.019854987 0.239878409 1.459631e+02
-11.629207 0.437677054 -0.15686137 -0.016772858 0.195055032 1.352385e+02
-11.312669 0.449008499 -0.12816677 -0.013704604 0.155035654 1.279765e+02
-8.236558 0.460339943 -0.09957734 -0.010647596 0.087699542 6.784089e+01
-7.662789 0.471671388 -0.07106908 -0.007599268 0.058231584 5.871833e+01
-6.752801 0.483002833 -0.04261848 -0.004557105 0.030773222 4.560033e+01
-6.707262 0.494334278 -0.01420234 -0.001518626 0.010185824 4.498736e+01
-6.402439 0.505665722 0.01420234 0.001518626 -0.009722911 4.099122e+01
-5.446904 0.516997167 0.04261848 0.004557105 -0.024822110 2.966876e+01
-3.537785 0.528328612 0.07106908 0.007599268 -0.026884576 1.251592e+01
-2.824941 0.539660057 0.09957734 0.010647596 -0.030078835 7.980294e+00
-2.745208 0.550991501 0.12816677 0.013704604 -0.037621996 7.536170e+00
-0.195089 0.562322946 0.15686137 0.016772858 -0.003272200 3.805971e-02
1.399296 0.573654391 0.18568573 0.019854987 0.027782994 1.958028e+00
5.363331 0.584985836 0.21466524 0.022953704 0.123108313 2.876532e+01
6.700640 0.596317280 0.24382619 0.026071824 0.174697904 4.489858e+01
7.386314 0.607648725 0.27319601 0.029212277 0.215771059 5.455764e+01
9.099900 0.618980170 0.30280344 0.032378138 0.294637808 8.280817e+01
12.433611 0.630311615 0.33267878 0.035572645 0.442296424 1.545947e+02
16.718018 0.641643059 0.36285409 0.038799229 0.648646203 2.794921e+02
18.093192 0.652974504 0.39336354 0.042061540 0.761027520 3.273636e+02
18.801816 0.664305949 0.42424369 0.045363489 0.852915978 3.535083e+02
19.168108 0.675637394 0.45553386 0.048709282 0.933664777 3.674164e+02
19.219211 0.686968839 0.48727661 0.052103467 1.001387528 3.693781e+02
20.334434 0.698300283 0.51951819 0.055550992 1.129598008 4.134892e+02
24.909926 0.709631728 0.55230918 0.059057264 1.471112049 6.205044e+02
26.236229 0.720963173 0.58570518 0.062628228 1.643128534 6.883397e+02
30.924022 0.732294618 0.61976766 0.066270458 2.049349072 9.562951e+02
32.253952 0.743626062 0.65456498 0.069991263 2.257494854 1.040317e+03
32.529367 0.754957507 0.69017366 0.073798824 2.400629035 1.058160e+03
32.675968 0.766288952 0.72667986 0.077702356 2.538999708 1.067719e+03
33.275839 0.777620397 0.76418130 0.081712307 2.719045583 1.107281e+03
36.031430 0.788951841 0.80278966 0.085840618 3.092960242 1.298264e+03
37.147186 0.800283286 0.84263354 0.090101040 3.347000059 1.379913e+03
40.320875 0.811614731 0.88386232 0.094509548 3.810707636 1.625773e+03
44.334467 0.822946176 0.92665123 0.099084876 4.392875123 1.965545e+03
46.907165 0.834277620 0.97120790 0.103849228 4.871272904 2.200282e+03
54.418366 0.845609065 1.01778137 0.108829231 5.922308882 2.961359e+03
55.091131 0.856940510 1.06667420 0.114057239 6.283542333 3.035033e+03
55.470305 0.868271955 1.11825971 0.119573169 6.632760113 3.076955e+03
62.939597 0.879603399 1.17300649 0.125427129 7.894332885 3.961393e+03
66.478628 0.890934844 1.23151500 0.131683320 8.754126443 4.419408e+03
67.426518 0.902266289 1.29457343 0.138426027 9.333585010 4.546335e+03
67.603959 0.913597734 1.36324747 0.145769197 9.854574914 4.570295e+03
69.707122 0.924929178 1.43903134 0.153872609 10.726016772 4.859083e+03
69.843246 0.936260623 1.52411994 0.162970954 11.382420482 4.878079e+03
74.848732 0.947592068 1.62194155 0.173430814 12.981076532 5.602333e+03
112.729191 0.958923513 1.73832835 0.185875811 20.953629849 1.270787e+04
163.795081 0.970254958 1.88455395 0.201511408 33.006577315 2.682883e+04
198.660139 0.981586402 2.08767462 0.226331231 44.962993843 3.946585e+04
209.375830 0.992917847 2.45306927 0.286093929 59.901153719 4.383824e+04
Fuente: Elaboración propia

Calculo estadistico W

W <- (sum(tabla_SW$ai_ui)^2)/sum(tabla_SW$ui2)
print(W)
## [1] 0.9413208

Calculo de Wn y su Pvalue

mu<-0.0038915*log(n)^3-0.083751*log(n)^2-0.31082*log(n)-1.5861
sigma<-exp(0.0030302*log(n)^2-0.082676*log(n)-0.4803)
Wn<-(log(1-W)-mu)/sigma
print(Wn)
## [1] 3.241867
p.value <- pnorm(Wn, lower.tail = FALSE)
print(p.value)
## [1] 0.0005937472
library(fastGraph)
shadeDist(Wn,ddist = "dnorm",lower.tail = FALSE)

Dado que el valor p (0.0005937472) es menor que el nivel de significancia (0.05), se rechaza la hipótesis nula. Por lo tanto, se concluye que los residuos no siguen una distribución normal N(0, σ²). # Usando la libreria stats

salida_SW <- shapiro.test(modelo_estimado$residuals)
print(salida_SW)
## 
##  Shapiro-Wilk normality test
## 
## data:  modelo_estimado$residuals
## W = 0.94132, p-value = 0.0005937

Calculando nuevamente el valor de Wn

Wn_salida <- qnorm(salida_SW$p.value, lower.tail = FALSE)
print(Wn_salida)
## [1] 3.241867