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Overview. Introduction to AMOS User Interface AMOS Graphics Examples of using AMOS Predictors of Problem Drinking using Path analysis. SEM Software. Several different packages exist EQS, LISREL, MPLUS, AMOS , SAS, ... Provide simultaneously overall tests of model fit

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Overview l.jpg
Overview

  • Introduction to AMOS

    • User Interface

    • AMOS Graphics

  • Examples of using AMOS

    • Predictors of Problem Drinking using Path analysis


Sem software l.jpg
SEM Software

  • Several different packages exist

    • EQS, LISREL, MPLUS, AMOS, SAS, ...

  • Provide simultaneously overall tests of

    • model fit

    • individual parameter estimate tests

  • May compare simultaneously

    • Regression coefficients

    • Means

    • Variances

      even across multiple between-subjects groups


Amos advantages l.jpg
AMOS Advantages

  • Easy to use for visual SEM ( Structural Equation Modeling).

  • Easy to modify, view the model

  • Publication –quality graphics


Structural equation modeling sem l.jpg
Structural Equation Modeling (SEM)

  • An extension of Regression and general Linear Models

  • Also can fit more complex models, like confirmatory factor analysis and longitudinal data.


Family tree of sem l.jpg
Family Tree of SEM

Latent

Growth

Curve

Analysis

T-test

ANOVA

Multi-way

ANOVA

Repeated

Measure

Designs

Growth

Curve

Analysis

Structural

Equation

Modeling

Multiple

Regression

Path

Analysis

Bivariate

Correlation

Confirmatory

Factor

Analysis

Factor

Analysis

Exploratory

Factor

Analysis


Structural equation modeling sem6 l.jpg
Structural Equation Modeling (SEM)

  • Observed variables =measured

  • Latent variables=unobserved

  • Exogenous variables=independent

  • Endogenous variables =dependent


Structural equation graphs l.jpg

.10

: R2

Error

.15

Structural Equation Graphs

Observed

Variable

: Loading

Latent

Variable


Example condom use model l.jpg

Observed variables for

Impulsive decision making

Example: Condom Use Model

IDMA1R

IDMC1R

IDME1R

IDMJ1R

Gender

Impulsive

Decision Making

Impulsive Decision Making

Peer norms

about condoms

Condom attitude

Legend

Latent

Variables

Observed

Variables

Condom use

.15

Loadings


Example condom use model9 l.jpg

Dependent

Dependent

Dependent

Example: Condom Use Model

Independent

IDMA1R

IDMC1R

IDME1R

IDMJ1R

Gender

Impulsive

Decision Making

Peer norms

about condoms

Independent

Condom attitude

Legend

Condom use

Latent

Variables

Observed

Variables

.15

Loadings

Dependent


Example condom use model10 l.jpg
Example: Condom Use Model

eidm1

eidm2

eidm4

eidm2

IDMA1R

IDMC1R

IDME1R

IDMJ1R

Gender

Impulsive

Decision Making

Condom attitude

Peer norms

about condoms

efr1

eiss

Legend

Condom use

Latent

Variables

Observed

Variables

eSXYRC1

.15

Loadings


Example condom use model11 l.jpg
Example: Condom Use Model

eidm1

eidm2

eidm4

eidm2

IDMA1R

IDMC1R

IDME1R

IDMJ1R

SEX1

Gender

Impulsive

Decision Making

efr1

Peer norms

about condoms

Condom attitude

Legend

Condom use

eiss

Latent

Variables

Observed

Variables

eSXYRC1

.15

Loadings


Example condom use model12 l.jpg

.28 .24 .48 .45

.03

.05

.15

Example: Condom Use Model

eidm1

eidm2

eidm4

eidm2

IDMA1R

IDMC1R

IDME1R

IDMJ1R

Gender

.49

.69

.67

-.06

.53

Impulsive

Decision Making

-.19

-.10

-.15

.13

Peer norms

about condoms

efr1

Condom attitude

.11

.38

Legend

Condom use

eiss

Latent

Variables

Observed

Variables

eSXYRC1

.15

Loadings


Amos components l.jpg
AMOS Components

  • AMOS Graphics

    • draw SEM graphs

    • runs SEM models using graphs

  • AMOS Basic

    • runs SEM models using syntax


Starting amos graphics l.jpg
Starting AMOS Graphics

Start

 Programs

 Amos 6

 Amos Graphics


Reading data into amos l.jpg
Reading Data into AMOS

  • File Data Files

  • The following dialog appears:


Reading data into amos16 l.jpg
Reading Data into AMOS

  • Click onFile Nameto specify the name of the data file

  • Currently AMOS reads the following data file formats: 

    • Access

    • dBase 3 – 5

    • Microsft Excel 3, 4, 5, and 97

    • FoxPro 2.0, 2.5 and 2.6

    • Lotus wk1, wk3, and wk4

    • SPSS*.sav files, versions 7.0.2 through 15.0 (both raw data and matrix formats)


Reading data into amos17 l.jpg
Reading Data into AMOS

  • Example USED today:

    • Predicting parental monitoring and problem drinking using a PATH DIAGRAM.

  • DATASET: only_valid_path_feb19_2007-n754.sav

    this file is in the “DROP” folder on desktop


Drawing in amos l.jpg

  • To draw an observed variable, click "Diagram" on the top menu, and click "Draw Observed." Move the cursor to the place where you want to place an observed variable and click your mouse. Drag the box in order to adjust the size of the box. You can also use     in the tool box to draw observed variables.

2. Unobserved variables can be drawn

similarly. Click "Diagram" and

"Draw Unobserved." Unobserved

variables are shown as circles.

You may also use      in the toolbox

to draw unobserved variables.

Drawing in AMOS

  • In Amos Graphics, a model can be specified by drawing a diagram on the screen


Drawing in amos19 l.jpg
Drawing in AMOS menu, and click "

  • To draw a path, Click “Diagram” on the top menu and click “Draw Path”.

  • Instead of using the top menu, you may use the Tool Box buttons to draw arrows ( and ).


Drawing in amos20 l.jpg
Drawing in AMOS menu, and click "

  • To draw Error Term to the observed and unobserved variables.

  • Use “Unique Variable” button in the Tool Box. Click and then click a box or a circle to which you want to add errors or a unique variables.(When you use "Unique Variable" button, the path coefficient will be automatically constrained to 1.)


Drawing in amos21 l.jpg
Drawing in AMOS menu, and click "

  • Let us draw:


Naming the variables in amos l.jpg
Naming the variables in menu, and click "AMOS

  • To name a variable, Click “View” on the top menu and click “Object Properties”

  • Click on the box you want to name

    Click on the Texttab and enter the name of the variable in the Variable namefield and /or Variable Label


Naming the variables in amos23 l.jpg
Naming the variables in menu, and click "AMOS

  • Example: Name the variables


Constraining a parameter in amos l.jpg
Constraining a parameter in AMOS menu, and click "

  • The scale of the latent variable or variance of the latent variable has to be fixed to 1.

Click “Object Properties“, then on the arrow between PRNTMNT1 and eprnt.

Click on the Parameterstab and enter the value “1” in the Regression weightfield:


Improving the appearance of the path diagram l.jpg
Improving the appearance menu, and click "of the path diagram

  • You can change the appearance of your path diagram by moving objects around

  • To move an object, click on the Moveicon on the toolbar. You will notice that the picture of a little moving truck appears below your mouse pointer when you move into the drawing area. This lets you know the Movefunction is active.

  • Then click and hold down your left mouse button on the object you wish to move. With the mouse button still depressed, move the object to where you want it, and let go of your mouse button. Amos Graphicswill automatically redraw all connecting arrows.


Improving the appearance of the path diagram26 l.jpg
Improving the appearance of the path diagram menu, and click "

  • To change the size and shape of an object, first press the Change the shape of objectsicon on the toolbar.

  • You will notice that appears under the mouse pointer to let you know the Shapefunction is active.

  • Click and hold down your left mouse button on the object you wish to re-shape. Change the shape of the object to your liking and release the mouse button.

  • Change the shape of objectsalso works on two-headed arrows. Follow the same procedure to change the direction or arc of any double-headed arrow.


Improving the appearance of the path diagram27 l.jpg
Improving the appearance of the path diagram menu, and click "

  • If you make a mistake, there are always three icons on the toolbar to quickly bail you out: the Eraseand Undofunctions.

  • To erase an object, simply click on the Eraseicon and then click on the object you wish to erase.

  • To undo your last drawing activity, click on theUndoicon and your last activity disappears.

  • Each time you click Undo, your previous activity will be removed.

  • If you change your mind, click on Redoto restore a change.


Performing the analysis in amos l.jpg
Performing the menu, and click " analysis in AMOS

  • View® Analysis Propertiesand click on the Output tab.

  • There is also an Analysis Propertiesicon you can click on the toolbar. Either way, the Outputtab gives you the following options:


Performing the analysis in amos29 l.jpg
Performing the analysis in AMOS menu, and click "

  • For our example, check the Minimization history, Standardized estimates, and Squared multiple correlationsboxes. (We are doing this because these are so commonly used in analysis).

  • To run AMOS, click on the Calculate estimatesicon on the toolbar.

    • AMOS will want to save this problem to a file.

    • if you have given it no filename, the Save Asdialog box will appear. Give the problem a file name; let us say, tutorial1:


Results l.jpg
Results menu, and click "

  • When AMOS has completed the calculations, you havetwo options for viewing the output:

    • text output,

    • graphics output.

  • For text output, click the View Text Output icon on the toolbar.

  • Here is a portion of the text output for this problem:


Slide31 l.jpg

Results for Path Model menu, and click "

The model is recursive. Sample size = 754

Chi-square=49.984Degrees of Freedom =9

Maximum Likelihood Estimates

Regression Weights: (Group number 1 - Default model)




Viewing the graphics output in amos l.jpg
Viewing the graphics output in AMOS model)

  • To view the graphics output, click the View outputicon next to the drawing area.

  • Chose to view either unstandardizedor (if you selected this option) standardizedestimates by click one or the other in the Parameter Formatspanel next to your drawing area:



Slide39 l.jpg

Improving the appearance of the path diagram model)

To move the parameters, click on the “Move Parameter values” and then click on the path, and move the parameter


Conclusion amos in nutshell l.jpg
Conclusion: Amos In nutshell model)

Today we learned ONE thing:

how to draw a model in AMOS

Topics for the next few weeks :

  • assess and interpret the models

  • compare models

  • analyze more complex models


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