I'm an absolute beginner with R and try to do a SEM.
I had first warnings because of a high variance in my data. I performed a z-standardization and now I have the error
Error in lav_samplestats_icov(COV = cov[[g]], ridge = ridge, x.idx = x.idx[[g]], :
lavaan ERROR: sample covariance matrix is not positive-definite
.
But I dont know, how to fix that.
Has somebody a suggestion?
I use the following code:
###------------------------
### Loading packages
###------------------------
library(lavaan)
library(lme4)
library(nlme)
library(reshape)
library(robustbase)
library(robustlmm)
library(WRS2)
library(psych)
library(MASS)
library(reshape2)
library(robmed)
library(semPlot)
###------------------------
### PATH MODEL
###------------------------
sem.MODELL28 <- '
ZMEAN_Spende_2 ~ ZMEAN_Schutzbereitschaft + ZMEAN_PMT_Barrieren + ZMEAN_PMT_response_efficacy + ZMEAN_PMT_self_efficacy + ZMEAN_PMT_ ethical_emotions + ZMEAN_PMT_Vulnerability + ZMEAN_PMT_Severity + ZMean_Einstellungen_gesamt + Summe_Quiz_richtig_falsch + PA01 + PA29_01 + PA07
ZMEAN_Schutzbereitschaft ~ ZMEAN_PMT_Barrieren + ZMEAN_PMT_response_efficacy + ZMEAN_PMT_self_efficacy + ZMEAN_PMT_ ethical_emotions + ZMEAN_PMT_Vulnerability + ZMEAN_PMT_Severity + ZMean_Einstellungen_gesamt + ZSumme_Quiz_richtig_falsch + ZPA01 + ZPA29_01 + ZPA07
ZMEAN_PMT_Barrieren ~ ZMean_Einstellungen_gesamt + ZSumme_Quiz_richtig_falsch + ZPA01 + ZPA29_01 + ZPA07
ZMEAN_PMT_response_efficacy ~ ZMean_Einstellungen_gesamt + ZSumme_Quiz_richtig_falsch + ZPA01 + ZPA29_01 + ZPA07
ZMEAN_PMT_self_efficacy ~ ZMean_Einstellungen_gesamt + ZSumme_Quiz_richtig_falsch + ZPA01 + ZPA29_01 + ZPA07
ZMEAN_PMT_ ethical_emotions ~ ZMean_Einstellungen_gesamt + ZSumme_Quiz_richtig_falsch + ZPA01 + ZPA29_01 + ZPA07
ZMEAN_PMT_Vulnerability ~ ZMean_Einstellungen_gesamt + ZSumme_Quiz_richtig_falsch + ZPA01 + ZPA29_01 + ZPA07
ZMEAN_PMT_Severity ~ ZMean_Einstellungen_gesamt + ZSumme_Quiz_richtig_falsch + ZPA01 + ZPA29_01 + ZPA07
ZMean_Einstellungen_gesamt ~ ZSumme_Quiz_richtig_falsch + ZPA01 + ZPA29_01 + ZPA07
'
# fit the model
fitsem <- sem(sem.MODELL28, data=SPSS_DATEI_umbenannte_variablen_gekuerzt_ohne_divers_13_09_gekuerzt_Standardisierte_Variablen, estimator="MLR", test = "bootstrap")
# display summary output
summary(fitsem.MODELL28, fit.measures=TRUE, standardized = TRUE, rsquare = TRUE)