| title | author | output |
|---|---|---|
Edit A Structural Equation |
Keon-Woong Moon |
html_document |
The classic Holzinger and Swineford (1939) dataset consists of mental ability test scores of seventh- and eighth-grade children from two different schools (Pasteur and Grant-White). In the original dataset (available in the MBESS package), there are scores for 26 tests. However, a smaller subset with 9 variables is more widely used in the literature. A Confirmatory Factor Analysis(CFA) model that is often proposed for these 9 variables consists of three latent variables (or factors), each with three indicators:
- a
visualfactor measured by 3 variables: x1, x2 and x3 - a
textualfactor measured by 3 variables: x4, x5 and x6 - a
speedfactor measured by 3 variables: x7, x8 and x9
You can insert/edit the structural equation easily by the following steps.
- Choose left side variable(s) or enter the latent variable
- Select operator
- Choose right side variable(s)
(1) First, please enter the latent variable visual in the text input(arrow).
As you enter the latent variable visual, the left side of equation will be made and the operator =~ will be added(arrow). The operator =~ is used for latent variable definition which means is measured by.
The current set of operators is summarized in the table below.
| formula type | operator | mnemonic |
|---|---|---|
| latent variable selection | =~ |
is measured by |
| regression | ~ |
is regressed on |
| (residual) (co)variance | ~~ |
is correlated with |
| intercept | ~1 |
intercept |
| defined parameter | := |
is predefined as |
| equality constriant | == |
equals |
| non-equalty constraint | < |
is less than |
| non-equalty constraint | > |
is greater than |
(2) And then, please select the rigth side variables - x1,x2 and x3 - among the variables displayed in the selectInput.
(3) After selection of three variables, press the add to equation button.
The temporary equation just made will be added to the equation. The latent variable input box(1), temporary equation(2) and the selectInput(for rigth side variables) will be initialized.
Please repeat the step (1)-(3) to add the equation:
textual =~ x4 + x5 + x6
speed =~ x7 + x8 + x9
You can directly type the equation in the equation window just as a word processor.
