Path%20Analysis

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Path Analysis
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Remember What Multiple Regression Tells Us

• How each individual IV is related to the DV
• The total amount of variance explained in a DV
• Multiple regression is VERY DV CENTRIC!!!
• We know NOTHING about how the IVs are related

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What is Path Analysis?

• Another way to do Multiple Regression
• A special case of multiple regression where all
  the relationships among variables can be
  estimated simultaneously

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What do you mean Simultaneously?

• Estimate correlations among your IVs
• Estimate regression relationships in the model
• You can make all the variables related to one
  another and find out what the relationship is
  exactly!
• All the regression analyses we did in SPSS can be
  done in path analysis

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Example

• Lets say you are interested in the extent to
  which intellectual activities mediate the
  relationship between education and cognition

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SPSS

• SPSS tells you about mediation
• SPSS tells you the relationship between
• Intellectual activities and cognition
• Education and cognition
• SPSS doesnt tell you anything about the
  relationship between education and intellectual
  activities

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Path Analysis
R2 ?
R2 ?
a
b
Education
Activities
Cognition
c
All these parameters are estimated at the same
time!
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• If we wanted to get the same results in SPSS we
  would have to do a bunch of different models
• Education predicts cognition
• Activities predicts cognition
• Both Predict cognition
• If we had more than three variables you can see
  how this could get impossible

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A model like this would be impossible in SPSS
IV
Mediator IV
DV
IV
Mediator IV
IV
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Benefits of Path Analysis

• Estimate all the relationships among all
  variables SIMULTANEOUSLY
• Able to test various hypothesis regarding
  different relationships
• Most programs you do path analysis in having
  Missing Data Estimation procedures!!!
• SPSS uses list-wise deletion

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Statistical Packages for Path Analysis

• Path analysis is the precursor to Structural
  Equation Modeling
• Any SEM program can do path analysis
• AMOS
• LISREL
• EQS

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AMOS

• AMOS is now bundled with SPSS
• It is the EASIEST program to use
• Its ease is based on the fact that you actually
  DRAW your models right in the program!!!

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AMOS Steps

• Open AMOS
• Tell AMOS what SPSS data set to use
• Draw your variables in AMOS
• Select estimation and output options
• Draw your model(s)
• Run your model

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(1) Open AMOS
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(2) Tell AMOS what SPSS data set to use

• Select FILE on the top tool bar
• Select DATA FILE from the drop down menu

Click on File Name and select your SPSS data set
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Drawing Tool Bar
(3) Draw your variables in AMOS
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Draw Your Variables
You click on this icon to draw a box in AMOS!
Variables are represented by a box
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You write the NAME of your variable here
You RIGHT CLICK on your variable box to get the
Object Properties
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(4) Select estimation and output options

• Select VIEW on the top tool bar
• Select ANALYSIS PROPERTIES from the drop down
  menu

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(5) Draw your model(s)
age
memory
Regression Path
Correlations
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DV needs a way indicate variance not explained by
AGE
0,
Error_1
1
age
memory
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AMOS practice

• Education and activity engagement are predictors
  of cognition. Also allow education and activity
  to correlate
• EDUCATION (educ), activity (activ), cognition
  (cog)

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