Mediation MODEL

data <- read.table(file = "MASEM_Mediere1_Cluster.dat", header = TRUE)
head(data)

nvar <- 6
varnames <- c ("v1 ","v2","v3","v4","v5","v6")
labels <- list (varnames,varnames)
cordat <- list ()
for (i in 1 :nrow (data)){
cordat[[i]] <- vec2symMat ( as.matrix (data[i,3 : 17]),
diag = FALSE)
dimnames (cordat[[i]]) <- labels
}

for (i in 1 :length (cordat)){
for (j in 1 :nrow (cordat[[i]])){
if ( sum ( is.na (cordat[[i]][j,])) == nvar-1)
{cordat[[i]][j,j] <- NA}
}}

cordat[[13]]

for (i in 1:length(cordat)){ 
for (j in 1:nrow(cordat[[i]])){ 
  for (k in 1:nvar){         
     if (is.na(cordat[[i]][j,k])==TRUE 
        &is.na(cordat[[i]][j,j])!=TRUE 
        &is.na(cordat[[i]][k,k])!=TRUE){ 
 if(sum(is.na(cordat[[i]])[j,])>sum(is.na(cordat[[i]])[k,])) 
   {cordat[[i]][k,k] <- NA} 
if(sum(is.na(cordat[[i]])[j,])<=sum(is.na(cordat[[i]])[k,])) 
   {cordat[[i]][j,j] <- NA}   
}}}}

stage1random <- tssem1 (Cov=cordat, n=data$N, method="REM")
stage1random <- rerun (stage1random, autofixtau2 = TRUE)
summary (stage1random)

A <- create.mxMatrix( 
c( 0 , 0 , 0 , 0 , 0 , 0,
"0.1*b21", 0 , "0.1*b23", 0 , 0 , 0,
0 , 0, 0 , 0 , 0 , 0,
"0.1*b41", "0.1*b42", 0 , 0 , 0 , 0,
0, "0.1*b52", "0.1*b53","0.1*b54", 0 , 0,
0 , "0.1*b62" , "0.1*b63","0.1*b64", 0, 0),
      type = "Full", 
      nrow = 6, 
      ncol = 6, 
      byrow = TRUE, 
      name = "A", 
      dimnames = list(varnames,varnames))
dimnames(A)[[1]] <- dimnames(A)[[2]] <- c("A","B","C","D","E","F")

S <- create.mxMatrix( 
c(1, 
0, "1*p22",
"0.1*p31",0, 1, 
0,0,0,"1*p44",
0,0,0,0,"1*p55",
0,0,0,0,"0.1*p65","1*p66"),  
type="Symm", byrow = TRUE, name="S", 
      dimnames = list(varnames,varnames))
dimnames(S)[[1]] <- dimnames(S)[[2]] <- c("A","B","C","D","E","F")

stage2 <- tssem2(stage1random, Amatrix=A, Smatrix=S, 
diag.constraints=FALSE, intervals="LB", 
mx.algebras=list(Ind125=mxAlgebra(b21*b52,name="Ind125"), 
                              Ind126=mxAlgebra(b21*b62,name="Ind126"),
                              Ind145=mxAlgebra(b41*b54,name="Ind145"),
                              Ind146=mxAlgebra(b41*b64,name="Ind146"),
                              Ind325=mxAlgebra(b23*b52,name="Ind325"),
                              Ind326=mxAlgebra(b23*b62,name="Ind326"),
                        Ind1245=mxAlgebra(b21*b42*b54,name="Ind1245"),
                       Ind1246=mxAlgebra(b21*b42*b64,name="Ind1246")))

SUBGOUP ANALYSIS

cordat_lo <- cordat[data$m1<2]
N_lo <- data$N[data$m1<2]
cordat_hi <- cordat[data$m1>1]
N_hi <- data$N[data$m1>1]

stage1random_lo <- tssem1(cov=cordat_lo, n=N_lo,  
                          method="REM", RE.type="Diag")

stage1random_hi <- tssem1(cov=cordat_hi, n=N_hi,  
                          method="REM", RE.type="Diag")