Carregando pacotes

#Pacote Alpha Cronbach
library(psych)
#Pacotes para CFA
library(lavaan) 
library(semTools) 
library(semPlot)

Carregando a base de dados

data.cfa <- read.csv2("C:/Users/Daniel/Desktop/Projetos/CFA/cfa.csv")
head(data.cfa)
##   COM1 COM2 COM3 COM4 DED1 DED2 DED3 DED4 BEN1 BEN2 BEN3 BEN4
## 1    4    5    4    5    5    3    5    5    5    5    3    5
## 2    2    2    1    4    5    4    4    4    5    5    2    5
## 3    2    2    2    4    2    1    2    4    5    5    3    4
## 4    5    5    5    5    5    5    5    5    5    5    5    5
## 5    5    5    5    3    5    4    5    5    4    5    2    5
## 6    5    5    4    5    3    5    5    3    5    5    3    5

Os dados incluem quatro itens para cada dimensão de Competência, Dedicação e Benevolência. Estas três dimensões constituem o constructo de trustworthiness, segundo Nooteboom (2002).

data.cfa$comtotal <- (data.cfa$COM1 + data.cfa$COM2 + data.cfa$COM3 + data.cfa$COM4) / 4
cor(data.cfa[1:4], data.cfa[13])
##       comtotal
## COM1 0.8952040
## COM2 0.7607075
## COM3 0.8190807
## COM4 0.7128979
data.cfa$dedtotal <- (data.cfa$DED1 + data.cfa$DED2 + data.cfa$DED3 + data.cfa$DED4) / 4
cor(data.cfa[5:8], data.cfa[14])
##       dedtotal
## DED1 0.8915662
## DED2 0.7607183
## DED3 0.8408274
## DED4 0.8879951
data.cfa$bentotal <- (data.cfa$BEN1 + data.cfa$BEN2 + data.cfa$BEN3 + data.cfa$BEN4) / 4
cor(data.cfa[9:12], data.cfa[15])
##       bentotal
## BEN1 0.5130898
## BEN2 0.6990352
## BEN3 0.6832269
## BEN4 0.7805646
pairs(data.cfa[13:15])

Alpha de Cronbach

cronbachalpha.cfa <- data.frame(data.cfa[1:12])


alpha(cronbachalpha.cfa)
## 
## Reliability analysis   
## Call: alpha(x = cronbachalpha.cfa)
## 
##   raw_alpha std.alpha G6(smc) average_r S/N   ase mean   sd median_r
##       0.89      0.89    0.91       0.4 8.1 0.011  3.5 0.87     0.39
## 
##  lower alpha upper     95% confidence boundaries
## 0.87 0.89 0.91 
## 
##  Reliability if an item is dropped:
##      raw_alpha std.alpha G6(smc) average_r S/N alpha se var.r med.r
## COM1      0.87      0.87    0.89      0.39 7.0    0.013 0.033  0.38
## COM2      0.89      0.89    0.91      0.43 8.2    0.011 0.031  0.42
## COM3      0.87      0.88    0.90      0.39 7.0    0.013 0.035  0.38
## COM4      0.88      0.89    0.91      0.42 7.9    0.012 0.038  0.42
## DED1      0.87      0.87    0.89      0.38 6.7    0.014 0.031  0.38
## DED2      0.88      0.88    0.90      0.41 7.5    0.012 0.038  0.38
## DED3      0.87      0.87    0.89      0.38 6.9    0.013 0.033  0.38
## DED4      0.87      0.87    0.89      0.38 6.8    0.013 0.033  0.38
## BEN1      0.89      0.90    0.91      0.44 8.6    0.011 0.033  0.44
## BEN2      0.90      0.90    0.91      0.44 8.8    0.010 0.028  0.44
## BEN3      0.88      0.88    0.91      0.41 7.6    0.012 0.036  0.39
## BEN4      0.87      0.87    0.89      0.39 6.9    0.013 0.033  0.38
## 
##  Item statistics 
##        n raw.r std.r r.cor r.drop mean   sd
## COM1 200  0.78  0.78  0.78   0.73  3.2 1.33
## COM2 200  0.52  0.52  0.47   0.42  3.4 1.40
## COM3 200  0.78  0.77  0.76   0.72  2.9 1.38
## COM4 200  0.58  0.59  0.53   0.50  3.7 1.27
## DED1 200  0.85  0.85  0.85   0.81  3.3 1.40
## DED2 200  0.68  0.66  0.62   0.59  2.8 1.44
## DED3 200  0.80  0.81  0.80   0.76  3.7 1.24
## DED4 200  0.82  0.82  0.82   0.77  3.5 1.39
## BEN1 200  0.39  0.44  0.36   0.33  4.7 0.74
## BEN2 200  0.43  0.41  0.33   0.29  3.7 1.59
## BEN3 200  0.64  0.65  0.60   0.57  2.9 1.16
## BEN4 200  0.78  0.79  0.79   0.73  3.8 1.15
## 
## Non missing response frequency for each item
##         1    2    3    4    5 miss
## COM1 0.12 0.25 0.18 0.25 0.20    0
## COM2 0.12 0.18 0.19 0.20 0.30    0
## COM3 0.18 0.30 0.15 0.20 0.18    0
## COM4 0.06 0.16 0.14 0.28 0.36    0
## DED1 0.13 0.18 0.22 0.18 0.30    0
## DED2 0.24 0.24 0.23 0.08 0.20    0
## DED3 0.06 0.14 0.16 0.30 0.34    0
## DED4 0.10 0.20 0.14 0.22 0.33    0
## BEN1 0.00 0.02 0.08 0.09 0.80    0
## BEN2 0.19 0.06 0.14 0.08 0.53    0
## BEN3 0.16 0.14 0.46 0.12 0.10    0
## BEN4 0.04 0.08 0.22 0.27 0.38    0

Análise Fatorial Confirmatória

Especificando o modelo e estimando os parâmetros

mod_lat <- '
lat_COM =~ COM1 + COM2 + COM3 + COM4
lat_DED =~ DED1 + DED2 + DED3 + DED4
lat_BEN =~ BEN1 + BEN2 + BEN3 + BEN4
'

mod_lat_fit <- cfa(mod_lat, data=data.cfa, std.lv=FALSE)

summary(mod_lat_fit, fit.measures=TRUE, rsquare=TRUE, standardized=TRUE) 
## lavaan 0.6-3 ended normally after 53 iterations
## 
##   Optimization method                           NLMINB
##   Number of free parameters                         27
## 
##   Number of observations                           200
## 
##   Estimator                                         ML
##   Model Fit Test Statistic                     134.161
##   Degrees of freedom                                51
##   P-value (Chi-square)                           0.000
## 
## Model test baseline model:
## 
##   Minimum Function Test Statistic             1312.805
##   Degrees of freedom                                66
##   P-value                                        0.000
## 
## User model versus baseline model:
## 
##   Comparative Fit Index (CFI)                    0.933
##   Tucker-Lewis Index (TLI)                       0.914
## 
## Loglikelihood and Information Criteria:
## 
##   Loglikelihood user model (H0)              -3382.695
##   Loglikelihood unrestricted model (H1)      -3315.614
## 
##   Number of free parameters                         27
##   Akaike (AIC)                                6819.389
##   Bayesian (BIC)                              6908.444
##   Sample-size adjusted Bayesian (BIC)         6822.905
## 
## Root Mean Square Error of Approximation:
## 
##   RMSEA                                          0.090
##   90 Percent Confidence Interval          0.072  0.109
##   P-value RMSEA <= 0.05                          0.000
## 
## Standardized Root Mean Square Residual:
## 
##   SRMR                                           0.061
## 
## Parameter Estimates:
## 
##   Information                                 Expected
##   Information saturated (h1) model          Structured
##   Standard Errors                             Standard
## 
## Latent Variables:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##   lat_COM =~                                                            
##     COM1              1.000                               1.216    0.918
##     COM2              0.709    0.074    9.587    0.000    0.862    0.619
##     COM3              0.906    0.066   13.681    0.000    1.101    0.801
##     COM4              0.583    0.069    8.457    0.000    0.709    0.562
##   lat_DED =~                                                            
##     DED1              1.000                               1.240    0.890
##     DED2              0.676    0.074    9.170    0.000    0.839    0.586
##     DED3              0.823    0.053   15.448    0.000    1.020    0.823
##     DED4              0.956    0.057   16.652    0.000    1.186    0.856
##   lat_BEN =~                                                            
##     BEN1              1.000                               0.266    0.362
##     BEN2              2.112    0.580    3.641    0.000    0.562    0.353
##     BEN3              2.781    0.588    4.732    0.000    0.740    0.641
##     BEN4              3.642    0.721    5.051    0.000    0.969    0.843
## 
## Covariances:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##   lat_COM ~~                                                            
##     lat_DED           1.133    0.149    7.585    0.000    0.751    0.751
##     lat_BEN           0.228    0.054    4.256    0.000    0.705    0.705
##   lat_DED ~~                                                            
##     lat_BEN           0.322    0.071    4.536    0.000    0.975    0.975
## 
## Variances:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##    .COM1              0.275    0.071    3.901    0.000    0.275    0.157
##    .COM2              1.194    0.129    9.284    0.000    1.194    0.616
##    .COM3              0.679    0.089    7.635    0.000    0.679    0.359
##    .COM4              1.092    0.115    9.479    0.000    1.092    0.685
##    .DED1              0.403    0.058    6.959    0.000    0.403    0.208
##    .DED2              1.347    0.140    9.602    0.000    1.347    0.657
##    .DED3              0.497    0.059    8.364    0.000    0.497    0.323
##    .DED4              0.514    0.066    7.842    0.000    0.514    0.268
##    .BEN1              0.469    0.048    9.838    0.000    0.469    0.869
##    .BEN2              2.214    0.225    9.847    0.000    2.214    0.875
##    .BEN3              0.783    0.086    9.156    0.000    0.783    0.589
##    .BEN4              0.382    0.065    5.861    0.000    0.382    0.289
##     lat_COM           1.479    0.185    7.993    0.000    1.000    1.000
##     lat_DED           1.538    0.194    7.911    0.000    1.000    1.000
##     lat_BEN           0.071    0.028    2.524    0.012    1.000    1.000
## 
## R-Square:
##                    Estimate
##     COM1              0.843
##     COM2              0.384
##     COM3              0.641
##     COM4              0.315
##     DED1              0.792
##     DED2              0.343
##     DED3              0.677
##     DED4              0.732
##     BEN1              0.131
##     BEN2              0.125
##     BEN3              0.411
##     BEN4              0.711