Exercise

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).

Instructions

100 XP

Perceptual organization should include piccomp, block, and matrixreason.
Processing speed should include digsym and symbolsearch.
Analyze the model with the cfa() function.
Summarize the model with the summary() function.