Create a Four-Factor Model
The WAIS-III IQ scale has a proposed four-factor model structure with verbal comprehension, working memory, perceptual organization, and processing speed. You should analyze this structure to determine if the model fits the data and that there are no problems with the model. In this exercise, you should find a Heywood case that indicates potential problems with the model.
The data has been loaded for you and is called IQdata
. You can view the data using head(IQdata)
.
This exercise is part of the course
Structural Equation Modeling with lavaan in R
Exercise instructions
- Perceptual organization should include
piccomp
,block
, andmatrixreason
. - Processing speed should include
digsym
andsymbolsearch
. - Analyze the model with the
cfa()
function. - Summarize the model with the
summary()
function.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# Build a four-factor model
wais.model <- 'verbalcomp =~ vocab + simil + inform + compreh
workingmemory =~ arith + digspan + lnseq
perceptorg =~ ___
processing =~ ___'
# Analyze the model and include the data argument
wais.fit <- cfa(___)
# Summarize the model with fit.measures and standardized loadings
summary(___)