Analisa Reliabilitas

Skala Greed Avoidance terdiri dari 9 item dengan normor : 119, 126, 132, 138, 144, 151, 157, 163, 169

Pembuktian reliabilitas dilakukan berdasarkan analisa koefisien internal konsistensi Alpha Cornbach dengan hasil analisa sebagai berikut

library(knitr)
library(CTT)
FULLDATA<-read.csv("~/Documents/MTPI ANALYSIS/CPU-PU-PR300.csv")
GAD<-FULLDATA[,c("i119", "i126", "i132", "i138", "i144", "i151", "i157", "i163", "i169")]
library(CTT)
reliability(GAD)
## 
##  Number of Items 
##  9 
## 
##  Number of Examinees 
##  300 
## 
##  Coefficient Alpha 
##  0.823
responses<-GAD
#Item analysis
item.analysis <- 
  function(responses){
    require(CTT, warn.conflicts = FALSE, quietly = TRUE)
    (ctt.analysis <- CTT::reliability(responses, itemal = TRUE, NA.Delete = TRUE))
    
    # Mark items that are potentially problematic
    item.analysis <- data.frame(item.mean = ctt.analysis$itemMean,
                                alpha.del = ctt.analysis$alphaIfDeleted)
    return(item.analysis)
  }

dump("item.analysis", file = "item.analysis.R")

knitr::kable(item.analysis(responses), 
             align = "c",
             caption = "Item Analysis")
Item Analysis
item.mean alpha.del
i119 4.236667 0.8148740
i126 4.066667 0.8095230
i132 4.290000 0.8115936
i138 4.753333 0.8094555
i144 4.373333 0.7900109
i151 4.546667 0.7961929
i157 4.840000 0.8129773
i163 5.070000 0.8018938
i169 4.663333 0.7961115

Dari perhitungan di atas maka skala ini memiliki alpha cronbach sebesar 0.823 (Sangat Tinggi), dan pada tabel dibawahnya tidak satupun item dari skala GAD yang jika tidak diikutsertakan dapat menaikan nilai internal konsistensi maka semua item diikutsertakan.

Analisa Melalui Konfirmatory Analisa Factor (CFA)

KMO Bartleet

library(psych)
## 
## Attaching package: 'psych'
## The following object is masked from 'package:CTT':
## 
##     polyserial
library(Hmisc)
## Loading required package: lattice
## Loading required package: survival
## Loading required package: Formula
## Loading required package: ggplot2
## 
## Attaching package: 'ggplot2'
## The following objects are masked from 'package:psych':
## 
##     %+%, alpha
## 
## Attaching package: 'Hmisc'
## The following object is masked from 'package:psych':
## 
##     describe
## The following objects are masked from 'package:base':
## 
##     format.pval, round.POSIXt, trunc.POSIXt, units
rGAD<-cor(GAD)
KMO(rGAD)
## Kaiser-Meyer-Olkin factor adequacy
## Call: KMO(r = rGAD)
## Overall MSA =  0.84
## MSA for each item = 
## i119 i126 i132 i138 i144 i151 i157 i163 i169 
## 0.88 0.81 0.83 0.77 0.90 0.87 0.74 0.88 0.85

Hasil perhitungan KMO Bartlet > 0.5 mengijinkan meneruskan analisa faktor dapat dilanjutkan dan nilai MSA tidak ada satupun yang nilainya <0.5 artinya semua item dapat dilibatkan dalam analisa faktor

CFA

library(lavaan)
## This is lavaan 0.5-23.1097
## lavaan is BETA software! Please report any bugs.
## 
## Attaching package: 'lavaan'
## The following object is masked from 'package:psych':
## 
##     cor2cov
library(semPlot)
library(knitr)
library(semTools)
## 
## ###############################################################################
## This is semTools 0.4-14
## All users of R (or SEM) are invited to submit functions or ideas for functions.
## ###############################################################################
## 
## Attaching package: 'semTools'
## The following object is masked from 'package:psych':
## 
##     skew
## The following object is masked from 'package:CTT':
## 
##     reliability
#CFA
one.model = "GAD =~ i119 + i126 + i132 + i138 + i144 + i151 + i157 + i163 +i169"
#Run the model
one.fit = cfa(one.model,data = GAD) 
semPaths(one.fit, whatLabels = "std", layout = "tree", intercepts = TRUE, residuals = TRUE)
## Warning in qgraph(Edgelist, labels = nLab, bidirectional = Bidir, directed
## = Directed, : The following arguments are not documented and likely not
## arguments of qgraph and thus ignored: loopRotation; residuals; residScale;
## residEdge; CircleEdgeEnd

summary(one.fit, standardized = TRUE, fit.measures = T, rsquare = TRUE)
## lavaan (0.5-23.1097) converged normally after  24 iterations
## 
##   Number of observations                           300
## 
##   Estimator                                         ML
##   Minimum Function Test Statistic              155.439
##   Degrees of freedom                                27
##   P-value (Chi-square)                           0.000
## 
## Model test baseline model:
## 
##   Minimum Function Test Statistic              803.541
##   Degrees of freedom                                36
##   P-value                                        0.000
## 
## User model versus baseline model:
## 
##   Comparative Fit Index (CFI)                    0.833
##   Tucker-Lewis Index (TLI)                       0.777
## 
## Loglikelihood and Information Criteria:
## 
##   Loglikelihood user model (H0)              -3476.016
##   Loglikelihood unrestricted model (H1)      -3398.296
## 
##   Number of free parameters                         18
##   Akaike (AIC)                                6988.031
##   Bayesian (BIC)                              7054.699
##   Sample-size adjusted Bayesian (BIC)         6997.614
## 
## Root Mean Square Error of Approximation:
## 
##   RMSEA                                          0.126
##   90 Percent Confidence Interval          0.107  0.145
##   P-value RMSEA <= 0.05                          0.000
## 
## Standardized Root Mean Square Residual:
## 
##   SRMR                                           0.076
## 
## Parameter Estimates:
## 
##   Information                                 Expected
##   Standard Errors                             Standard
## 
## Latent Variables:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##   GAD =~                                                                
##     i119              1.000                               0.562    0.495
##     i126              0.863    0.135    6.400    0.000    0.485    0.505
##     i132              0.910    0.143    6.360    0.000    0.511    0.500
##     i138              0.830    0.125    6.616    0.000    0.466    0.532
##     i144              1.364    0.175    7.775    0.000    0.766    0.723
##     i151              1.275    0.170    7.509    0.000    0.716    0.670
##     i157              0.811    0.126    6.447    0.000    0.455    0.511
##     i163              0.971    0.133    7.322    0.000    0.545    0.637
##     i169              1.307    0.172    7.585    0.000    0.734    0.685
## 
## Variances:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##    .i119              0.972    0.085   11.483    0.000    0.972    0.755
##    .i126              0.687    0.060   11.442    0.000    0.687    0.745
##    .i132              0.785    0.068   11.463    0.000    0.785    0.750
##    .i138              0.549    0.049   11.315    0.000    0.549    0.717
##    .i144              0.534    0.055    9.638    0.000    0.534    0.477
##    .i151              0.628    0.061   10.309    0.000    0.628    0.551
##    .i157              0.587    0.051   11.416    0.000    0.587    0.739
##    .i163              0.434    0.041   10.626    0.000    0.434    0.594
##    .i169              0.611    0.060   10.152    0.000    0.611    0.531
##     GAD               0.315    0.075    4.208    0.000    1.000    1.000
## 
## R-Square:
##                    Estimate
##     i119              0.245
##     i126              0.255
##     i132              0.250
##     i138              0.283
##     i144              0.523
##     i151              0.449
##     i157              0.261
##     i163              0.406
##     i169              0.469
fitmeasures(one.fit)
##                npar                fmin               chisq 
##              18.000               0.259             155.439 
##                  df              pvalue      baseline.chisq 
##              27.000               0.000             803.541 
##         baseline.df     baseline.pvalue                 cfi 
##              36.000               0.000               0.833 
##                 tli                nnfi                 rfi 
##               0.777               0.777               0.742 
##                 nfi                pnfi                 ifi 
##               0.807               0.605               0.835 
##                 rni                logl   unrestricted.logl 
##               0.833           -3476.016           -3398.296 
##                 aic                 bic              ntotal 
##            6988.031            7054.699             300.000 
##                bic2               rmsea      rmsea.ci.lower 
##            6997.614               0.126               0.107 
##      rmsea.ci.upper        rmsea.pvalue                 rmr 
##               0.145               0.000               0.069 
##          rmr_nomean                srmr        srmr_bentler 
##               0.069               0.076               0.076 
## srmr_bentler_nomean         srmr_bollen  srmr_bollen_nomean 
##               0.076               0.076               0.076 
##          srmr_mplus   srmr_mplus_nomean               cn_05 
##               0.076               0.076              78.419 
##               cn_01                 gfi                agfi 
##              91.639               0.897               0.828 
##                pgfi                 mfi                ecvi 
##               0.538               0.807               0.638
summary(one.fit, fit.measures=TRUE)
## lavaan (0.5-23.1097) converged normally after  24 iterations
## 
##   Number of observations                           300
## 
##   Estimator                                         ML
##   Minimum Function Test Statistic              155.439
##   Degrees of freedom                                27
##   P-value (Chi-square)                           0.000
## 
## Model test baseline model:
## 
##   Minimum Function Test Statistic              803.541
##   Degrees of freedom                                36
##   P-value                                        0.000
## 
## User model versus baseline model:
## 
##   Comparative Fit Index (CFI)                    0.833
##   Tucker-Lewis Index (TLI)                       0.777
## 
## Loglikelihood and Information Criteria:
## 
##   Loglikelihood user model (H0)              -3476.016
##   Loglikelihood unrestricted model (H1)      -3398.296
## 
##   Number of free parameters                         18
##   Akaike (AIC)                                6988.031
##   Bayesian (BIC)                              7054.699
##   Sample-size adjusted Bayesian (BIC)         6997.614
## 
## Root Mean Square Error of Approximation:
## 
##   RMSEA                                          0.126
##   90 Percent Confidence Interval          0.107  0.145
##   P-value RMSEA <= 0.05                          0.000
## 
## Standardized Root Mean Square Residual:
## 
##   SRMR                                           0.076
## 
## Parameter Estimates:
## 
##   Information                                 Expected
##   Standard Errors                             Standard
## 
## Latent Variables:
##                    Estimate  Std.Err  z-value  P(>|z|)
##   GAD =~                                              
##     i119              1.000                           
##     i126              0.863    0.135    6.400    0.000
##     i132              0.910    0.143    6.360    0.000
##     i138              0.830    0.125    6.616    0.000
##     i144              1.364    0.175    7.775    0.000
##     i151              1.275    0.170    7.509    0.000
##     i157              0.811    0.126    6.447    0.000
##     i163              0.971    0.133    7.322    0.000
##     i169              1.307    0.172    7.585    0.000
## 
## Variances:
##                    Estimate  Std.Err  z-value  P(>|z|)
##    .i119              0.972    0.085   11.483    0.000
##    .i126              0.687    0.060   11.442    0.000
##    .i132              0.785    0.068   11.463    0.000
##    .i138              0.549    0.049   11.315    0.000
##    .i144              0.534    0.055    9.638    0.000
##    .i151              0.628    0.061   10.309    0.000
##    .i157              0.587    0.051   11.416    0.000
##    .i163              0.434    0.041   10.626    0.000
##    .i169              0.611    0.060   10.152    0.000
##     GAD               0.315    0.075    4.208    0.000
parameterEstimates(one.fit, standardized=TRUE)
##     lhs op  rhs   est    se      z pvalue ci.lower ci.upper std.lv std.all
## 1   GAD =~ i119 1.000 0.000     NA     NA    1.000    1.000  0.562   0.495
## 2   GAD =~ i126 0.863 0.135  6.400      0    0.599    1.128  0.485   0.505
## 3   GAD =~ i132 0.910 0.143  6.360      0    0.630    1.191  0.511   0.500
## 4   GAD =~ i138 0.830 0.125  6.616      0    0.584    1.075  0.466   0.532
## 5   GAD =~ i144 1.364 0.175  7.775      0    1.020    1.707  0.766   0.723
## 6   GAD =~ i151 1.275 0.170  7.509      0    0.943    1.608  0.716   0.670
## 7   GAD =~ i157 0.811 0.126  6.447      0    0.564    1.057  0.455   0.511
## 8   GAD =~ i163 0.971 0.133  7.322      0    0.711    1.231  0.545   0.637
## 9   GAD =~ i169 1.307 0.172  7.585      0    0.970    1.645  0.734   0.685
## 10 i119 ~~ i119 0.972 0.085 11.483      0    0.806    1.138  0.972   0.755
## 11 i126 ~~ i126 0.687 0.060 11.442      0    0.569    0.805  0.687   0.745
## 12 i132 ~~ i132 0.785 0.068 11.463      0    0.650    0.919  0.785   0.750
## 13 i138 ~~ i138 0.549 0.049 11.315      0    0.454    0.644  0.549   0.717
## 14 i144 ~~ i144 0.534 0.055  9.638      0    0.426    0.643  0.534   0.477
## 15 i151 ~~ i151 0.628 0.061 10.309      0    0.509    0.748  0.628   0.551
## 16 i157 ~~ i157 0.587 0.051 11.416      0    0.486    0.688  0.587   0.739
## 17 i163 ~~ i163 0.434 0.041 10.626      0    0.354    0.515  0.434   0.594
## 18 i169 ~~ i169 0.611 0.060 10.152      0    0.493    0.729  0.611   0.531
## 19  GAD ~~  GAD 0.315 0.075  4.208      0    0.168    0.462  1.000   1.000
##    std.nox
## 1    0.495
## 2    0.505
## 3    0.500
## 4    0.532
## 5    0.723
## 6    0.670
## 7    0.511
## 8    0.637
## 9    0.685
## 10   0.755
## 11   0.745
## 12   0.750
## 13   0.717
## 14   0.477
## 15   0.551
## 16   0.739
## 17   0.594
## 18   0.531
## 19   1.000
summary(one.fit, fit.measures=TRUE, standardized=TRUE)
## lavaan (0.5-23.1097) converged normally after  24 iterations
## 
##   Number of observations                           300
## 
##   Estimator                                         ML
##   Minimum Function Test Statistic              155.439
##   Degrees of freedom                                27
##   P-value (Chi-square)                           0.000
## 
## Model test baseline model:
## 
##   Minimum Function Test Statistic              803.541
##   Degrees of freedom                                36
##   P-value                                        0.000
## 
## User model versus baseline model:
## 
##   Comparative Fit Index (CFI)                    0.833
##   Tucker-Lewis Index (TLI)                       0.777
## 
## Loglikelihood and Information Criteria:
## 
##   Loglikelihood user model (H0)              -3476.016
##   Loglikelihood unrestricted model (H1)      -3398.296
## 
##   Number of free parameters                         18
##   Akaike (AIC)                                6988.031
##   Bayesian (BIC)                              7054.699
##   Sample-size adjusted Bayesian (BIC)         6997.614
## 
## Root Mean Square Error of Approximation:
## 
##   RMSEA                                          0.126
##   90 Percent Confidence Interval          0.107  0.145
##   P-value RMSEA <= 0.05                          0.000
## 
## Standardized Root Mean Square Residual:
## 
##   SRMR                                           0.076
## 
## Parameter Estimates:
## 
##   Information                                 Expected
##   Standard Errors                             Standard
## 
## Latent Variables:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##   GAD =~                                                                
##     i119              1.000                               0.562    0.495
##     i126              0.863    0.135    6.400    0.000    0.485    0.505
##     i132              0.910    0.143    6.360    0.000    0.511    0.500
##     i138              0.830    0.125    6.616    0.000    0.466    0.532
##     i144              1.364    0.175    7.775    0.000    0.766    0.723
##     i151              1.275    0.170    7.509    0.000    0.716    0.670
##     i157              0.811    0.126    6.447    0.000    0.455    0.511
##     i163              0.971    0.133    7.322    0.000    0.545    0.637
##     i169              1.307    0.172    7.585    0.000    0.734    0.685
## 
## Variances:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##    .i119              0.972    0.085   11.483    0.000    0.972    0.755
##    .i126              0.687    0.060   11.442    0.000    0.687    0.745
##    .i132              0.785    0.068   11.463    0.000    0.785    0.750
##    .i138              0.549    0.049   11.315    0.000    0.549    0.717
##    .i144              0.534    0.055    9.638    0.000    0.534    0.477
##    .i151              0.628    0.061   10.309    0.000    0.628    0.551
##    .i157              0.587    0.051   11.416    0.000    0.587    0.739
##    .i163              0.434    0.041   10.626    0.000    0.434    0.594
##    .i169              0.611    0.060   10.152    0.000    0.611    0.531
##     GAD               0.315    0.075    4.208    0.000    1.000    1.000
library(knitr)
library(dplyr) 
## 
## Attaching package: 'dplyr'
## The following objects are masked from 'package:Hmisc':
## 
##     combine, src, summarize
## The following objects are masked from 'package:stats':
## 
##     filter, lag
## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union
library(tidyr)
parameterEstimates(one.fit, standardized=TRUE) %>% 
  filter(op == "=~") %>% 
  select('Latent Factor'=lhs, Indicator=rhs, B=est, SE=se, Z=z, 'p-value'=pvalue, Beta=std.all) %>% 
  kable(digits = 3, format="pandoc", caption="Factor Loadings")
Factor Loadings
Latent Factor Indicator B SE Z p-value Beta
GAD i119 1.000 0.000 NA NA 0.495
GAD i126 0.863 0.135 6.400 0 0.505
GAD i132 0.910 0.143 6.360 0 0.500
GAD i138 0.830 0.125 6.616 0 0.532
GAD i144 1.364 0.175 7.775 0 0.723
GAD i151 1.275 0.170 7.509 0 0.670
GAD i157 0.811 0.126 6.447 0 0.511
GAD i163 0.971 0.133 7.322 0 0.637
GAD i169 1.307 0.172 7.585 0 0.685

Parameter CFA sudah memenuhi model fit

OMEGA

## Loading required namespace: GPArotation
## Omega_h for 1 factor is not meaningful, just omega_t
## Warning in schmid(m, nfactors, fm, digits, rotate = rotate, n.obs =
## n.obs, : Omega_h and Omega_asymptotic are not meaningful with one factor
##  
## Call: omegaSem(m = GAD, nfactors = 1, n.obs = 3277)
## Omega 
## Call: omega(m = m, nfactors = nfactors, fm = fm, key = key, flip = flip, 
##     digits = digits, title = title, sl = sl, labels = labels, 
##     plot = plot, n.obs = n.obs, rotate = rotate, Phi = Phi, option = option)
## Alpha:                 0.82 
## G.6:                   0.83 
## Omega Hierarchical:    0.83 
## Omega H asymptotic:    1 
## Omega Total            0.83 
## 
## Schmid Leiman Factor loadings greater than  0.2 
##         g  F1*   h2   u2 p2
## i119 0.50      0.25 0.75  1
## i126 0.52      0.27 0.73  1
## i132 0.51      0.26 0.74  1
## i138 0.54      0.29 0.71  1
## i144 0.72      0.52 0.48  1
## i151 0.67      0.44 0.56  1
## i157 0.51      0.26 0.74  1
## i163 0.63      0.40 0.60  1
## i169 0.67      0.45 0.55  1
## 
## With eigenvalues of:
##   g F1* 
## 3.1 0.0 
## 
## general/max  3.775284e+16   max/min =   1
## mean percent general =  1    with sd =  0 and cv of  0 
## Explained Common Variance of the general factor =  1 
## 
## The degrees of freedom are 27  and the fit is  0.52 
## The number of observations was  300  with Chi Square =  152.88  with prob <  1.5e-19
## The root mean square of the residuals is  0.08 
## The df corrected root mean square of the residuals is  0.1
## RMSEA index =  0.126  and the 10 % confidence intervals are  0.106 0.144
## BIC =  -1.13
## 
## Compare this with the adequacy of just a general factor and no group factors
## The degrees of freedom for just the general factor are 27  and the fit is  0.52 
## The number of observations was  300  with Chi Square =  152.88  with prob <  1.5e-19
## The root mean square of the residuals is  0.08 
## The df corrected root mean square of the residuals is  0.1 
## 
## RMSEA index =  0.126  and the 10 % confidence intervals are  0.106 0.144
## BIC =  -1.13 
## 
## Measures of factor score adequacy             
##                                                  g F1*
## Correlation of scores with factors            0.92   0
## Multiple R square of scores with factors      0.84   0
## Minimum correlation of factor score estimates 0.68  -1
## 
##  Total, General and Subset omega for each subset
##                                                  g  F1*
## Omega total for total scores and subscales    0.83 0.83
## Omega general for total scores and subscales  0.83 0.83
## Omega group for total scores and subscales    0.00 0.00
## 
##  The following analyses were done using the  lavaan  package 
## 
##  With only 1 factor specified in the sem model, we can only calculate omega Total.
##  You should probably rerun the sem specifying either a bifactor or hierarchical model.
## 
##  Omega Total  from a confirmatory model using sem =  0.83 
## With loadings of 
##      loads   h2   u2   p2
## i119  0.49 0.24 0.76 1.00
## i126  0.50 0.25 0.75 1.00
## i132  0.50 0.25 0.75 1.00
## i138  0.53 0.28 0.72 1.00
## i144  0.72 0.52 0.48 1.00
## i151  0.67 0.45 0.55 1.00
## i157  0.51 0.26 0.74 1.00
## i163  0.64 0.40 0.60 1.02
## i169  0.68 0.47 0.53 0.98
## 
## With eigenvalues of:
## loads 
##   3.1 
## 
## The degrees of freedom of the confimatory model are  27  and the fit is  155.4388  with p =  0
## general/max  NA   max/min =   NA
## mean percent general =  1    with sd =  0.01 and cv of  0.01 
## Explained Common Variance of the general factor =  1 
## 
## To get the standard sem fit statistics, ask for summary on the fitted object

Nilai Omega yang sangat tinggi diperoleh

KESIMPULAN

Untuk skala Greed Avoidance, semua item dapat digunakan dengan bobot sesuai eigen valuesnya, dan nilai reliabilitas skalanya sangat tinggi 0.823 yang dibuktikan dengan Alpha Cronbach, prinsip unidimensionalitasnya sudah terjaga dapat dibuktikan dengan hasil analisa faktor konfirmatorynya.