Ejercicio 1

Carga de Datos

library(dplyr)
library(readr)
ejemplo_regresion <- read_csv("Econometria/ejemplo_regresion.csv")
head(ejemplo_regresion,n = 5)
## # A tibble: 5 × 3
##      X1    X2     Y
##   <dbl> <dbl> <dbl>
## 1  3.92  7298  0.75
## 2  3.61  6855  0.71
## 3  3.32  6636  0.66
## 4  3.07  6506  0.61
## 5  3.06  6450  0.7

Ejemplo de regresion lineal

library(stargazer)
options(scipen = 99999)
modelo_lineal<-lm(formula = Y~X1+X2,data = ejemplo_regresion)

#Usando summary 
summary(modelo_lineal)
## 
## Call:
## lm(formula = Y ~ X1 + X2, data = ejemplo_regresion)
## 
## Residuals:
##       Min        1Q    Median        3Q       Max 
## -0.085090 -0.039102 -0.003341  0.030236  0.105692 
## 
## Coefficients:
##                Estimate  Std. Error t value            Pr(>|t|)    
## (Intercept)  1.56449677  0.07939598  19.705 0.00000000000000182 ***
## X1           0.23719747  0.05555937   4.269            0.000313 ***
## X2          -0.00024908  0.00003205  -7.772 0.00000009508790794 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.0533 on 22 degrees of freedom
## Multiple R-squared:  0.8653, Adjusted R-squared:  0.8531 
## F-statistic: 70.66 on 2 and 22 DF,  p-value: 0.000000000265
#Usando stargazer
stargazer(modelo_lineal,title = "Modelo de Regresion",type = "text",digits = 6)
## 
## Modelo de Regresion
## ===============================================
##                         Dependent variable:    
##                     ---------------------------
##                                  Y             
## -----------------------------------------------
## X1                          0.237197***        
##                             (0.055559)         
##                                                
## X2                         -0.000249***        
##                             (0.000032)         
##                                                
## Constant                    1.564497***        
##                             (0.079396)         
##                                                
## -----------------------------------------------
## Observations                    25             
## R2                           0.865296          
## Adjusted R2                  0.853050          
## Residual Std. Error     0.053302 (df = 22)     
## F Statistic          70.660570*** (df = 2; 22) 
## ===============================================
## Note:               *p<0.1; **p<0.05; ***p<0.01

Objetos dentro del modelo lineal

Vector de coeficientes estimados

options(scipen = 999)
modelo_lineal$coefficients
##   (Intercept)            X1            X2 
##  1.5644967711  0.2371974748 -0.0002490793

Matriz de Varianza - Covarianza de los parametros

var_covar <- vcov(modelo_lineal)
print(var_covar)
##                  (Intercept)              X1                 X2
## (Intercept)  0.0063037218732  0.000240996434 -0.000000982806321
## X1           0.0002409964344  0.003086843196 -0.000001675537651
## X2          -0.0000009828063 -0.000001675538  0.000000001027106

Intervalos de confianza

confint(object = modelo_lineal, level = .95)
##                     2.5 %        97.5 %
## (Intercept)  1.3998395835  1.7291539588
## X1           0.1219744012  0.3524205485
## X2          -0.0003155438 -0.0001826148

Valores Ajustados

plot(modelo_lineal$fitted.values,main = "Valores Ajustados", ylab = "Y", xlab = "casos")

modelo_lineal$fitted.values %>% as.matrix()
##         [,1]
## 1  0.6765303
## 2  0.7133412
## 3  0.6991023
## 4  0.6721832
## 5  0.6837597
## 6  0.7075753
## 7  0.7397638
## 8  0.7585979
## 9  0.7943078
## 10 0.7935605
## 11 0.7984347
## 12 0.8272778
## 13 0.8021665
## 14 0.7992462
## 15 0.7544349
## 16 0.7339716
## 17 0.7048866
## 18 0.6930338
## 19 0.6350898
## 20 0.6127185
## 21 0.5701215
## 22 0.4796371
## 23 0.4374811
## 24 0.3953981
## 25 0.3773799

Residuos del modelo

plot(modelo_lineal$residuals,main = "Residuos", ylab = "Residuos", xlab = "casos")

modelo_lineal$residuals %>% as.matrix()
##            [,1]
## 1   0.073469743
## 2  -0.003341163
## 3  -0.039102258
## 4  -0.062183196
## 5   0.016240338
## 6   0.012424659
## 7   0.030236216
## 8  -0.018597878
## 9   0.105692240
## 10  0.026439478
## 11 -0.048434733
## 12 -0.057277771
## 13 -0.022166535
## 14  0.040753758
## 15  0.035565142
## 16 -0.033971640
## 17 -0.024886579
## 18  0.026966239
## 19 -0.085089833
## 20  0.017281530
## 21 -0.010121525
## 22 -0.069637086
## 23  0.072518915
## 24  0.074601871
## 25 -0.057379932

Ejercicio 2

Carga de Datos

library(readxl)
ejemplo_regresion_2 <- read_excel("Econometria/ejemplo_regresion_2.xlsx", 
    col_types = c("numeric", "numeric", "numeric"))
head(ejemplo_regresion_2,n = 5)
## # A tibble: 5 × 3
##       Y    X1    X2
##   <dbl> <dbl> <dbl>
## 1   320    50   7.4
## 2   450    53   5.1
## 3   370    60   4.2
## 4   470    63   3.9
## 5   420    69   1.4

Regresion lineal

library(stargazer)
options(scipen = 99999)
modelo_lineal_2<-lm(formula = Y~X1+X2+(X1*X2),data = ejemplo_regresion_2)


#Usando summary 
summary(modelo_lineal_2)
## 
## Call:
## lm(formula = Y ~ X1 + X2 + (X1 * X2), data = ejemplo_regresion_2)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -108.527  -37.595   -2.745   52.292  102.808 
## 
## Coefficients:
##              Estimate Std. Error t value Pr(>|t|)    
## (Intercept) 303.50401   71.54695   4.242 0.000621 ***
## X1            2.32927    0.47698   4.883 0.000166 ***
## X2          -25.07113   11.48487  -2.183 0.044283 *  
## X1:X2         0.28617    0.07681   3.726 0.001840 ** 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 67.68 on 16 degrees of freedom
## Multiple R-squared:  0.9634, Adjusted R-squared:  0.9566 
## F-statistic: 140.4 on 3 and 16 DF,  p-value: 0.00000000001054
#Usando stargazer
stargazer(modelo_lineal_2,title = "Modelo de Regresion",type = "text",digits = 6)
## 
## Modelo de Regresion
## ===============================================
##                         Dependent variable:    
##                     ---------------------------
##                                  Y             
## -----------------------------------------------
## X1                          2.329275***        
##                             (0.476982)         
##                                                
## X2                         -25.071130**        
##                             (11.484870)        
##                                                
## X1:X2                       0.286169***        
##                             (0.076813)         
##                                                
## Constant                   303.504000***       
##                             (71.546950)        
##                                                
## -----------------------------------------------
## Observations                    20             
## R2                           0.963414          
## Adjusted R2                  0.956554          
## Residual Std. Error     67.677750 (df = 16)    
## F Statistic         140.440600*** (df = 3; 16) 
## ===============================================
## Note:               *p<0.1; **p<0.05; ***p<0.01

Objetos dentro del modelo lineal

Vector de coeficientes estimados

options(scipen = 999)
modelo_lineal_2$coefficients
## (Intercept)          X1          X2       X1:X2 
## 303.5040143   2.3292746 -25.0711288   0.2861686

Matriz de Varianza - Covarianza de los parametros

var_covar_2 <- vcov(modelo_lineal_2)
print(var_covar_2)
##             (Intercept)           X1           X2        X1:X2
## (Intercept)  5118.96645 -31.10997447 -722.8989902  4.493190281
## X1            -31.10997   0.22751204    4.5755139 -0.033223456
## X2           -722.89899   4.57551391  131.9021598 -0.822206343
## X1:X2           4.49319  -0.03322346   -0.8222063  0.005900226

Intervalos de confianza

confint(object = modelo_lineal_2, level = .95)
##                   2.5 %      97.5 %
## (Intercept) 151.8312499 455.1767786
## X1            1.3181175   3.3404318
## X2          -49.4179582  -0.7242993
## X1:X2         0.1233324   0.4490047

Valores Ajustados

plot(modelo_lineal_2$fitted.values,main = "Valores Ajustados", ylab = "Y", xlab = "casos")

modelo_lineal_2$fitted.values %>% as.matrix()
##         [,1]
## 1   340.3238
## 2   376.4442
## 3   410.0762
## 4   422.7825
## 5   456.7683
## 6   490.9729
## 7   561.2516
## 8   572.4839
## 9   661.8956
## 10  805.2546
## 11  743.9514
## 12  802.6063
## 13  921.3246
## 14 1038.5268
## 15  966.3846
## 16  967.1923
## 17 1087.4101
## 18 1280.2249
## 19 1349.9604
## 20 1214.1649

Residuos del modelo

plot(modelo_lineal_2$residuals,main = "Residuos", ylab = "Residuos", xlab = "casos")

modelo_lineal_2$residuals %>% as.matrix()
##           [,1]
## 1   -20.323767
## 2    73.555820
## 3   -40.076233
## 4    47.217467
## 5   -36.768268
## 6     9.027138
## 7     8.748419
## 8    67.516125
## 9     8.104393
## 10  -25.254613
## 11  -53.951414
## 12 -102.606335
## 13  -11.324647
## 14 -108.526815
## 15  -26.384626
## 16  102.807683
## 17   72.589856
## 18  -70.224936
## 19  100.039646
## 20    5.835106