Exercise

# Create a Zero df Model

In the first chapter, we created a model of text-speed from the `HolzingerSwineford1939`

dataset with six manifest variables `x4`

, `x5`

, `x6`

, `x7`

, `x8`

, `x9`

. Create a model of only reading comprehension with `x4`

, `x5`

, and `x6`

.

This model should have zero degrees of freedom because it is not identified, as we are estimating as many parameters as we have options with only three manifest variables. Analyze the model to find zero degrees of freedom. `lavaan`

and the `HolzingerSwineford1939`

dataset have been loaded for you.

Instructions

**100 XP**

- Name your model
`text.model`

and your latent variable`text`

. - Use variables
`x4`

,`x5`

, and`x6`

as the manifest variables. - Use the
`cfa()`

function to analyze the model. - Use the
`summary()`

function to view the degrees of freedom.