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GRA 6020 Multivariate Statistics Confirmatory Factor Analysis. Ulf H. Olsson Professor of Statistics. CFA. The covariance matrices:. CFA and ML. k is the number of manifest variables.
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GRA 6020Multivariate StatisticsConfirmatory Factor Analysis Ulf H. Olsson Professor of Statistics
CFA • The covariance matrices: Ulf H. Olsson
CFA and ML k is the number of manifest variables. If the observed variables comes from a multivariate normal distribution, then Ulf H. Olsson
Testing Fit Ulf H. Olsson
Problems with the chi-square test • The chi-square tends to be large in large samples if the model does not hold • It is based on the assumption that the model holds in the population • It is assumed that the observed variables comes from a multivariate normal distribution • => The chi-square test might be to strict, since it is based on unreasonable assumptions?! Ulf H. Olsson
Univariate Normal Distribution Ulf H. Olsson
Bivariate normal distribution Ulf H. Olsson
J-te order Moments • Skewness • Kurtosis Ulf H. Olsson
Kurtosis Ulf H. Olsson
Standard Normal density functions Ulf H. Olsson
Alternative test- Testing Close fit Ulf H. Olsson
How to Use RMSEA • Use the 90% Confidence interval for EA • Use The P-value for EA • RMSEA as a descriptive Measure • RMSEA< 0.05 Good Fit • 0.05 < RMSEA < 0.08 Acceptable Fit • RMSEA > 0.10 Not Acceptable Fit Ulf H. Olsson
Other Fit Indices • CN • RMR • GFI • AGFI • Evaluation of Reliability • MI: Modification Indices Ulf H. Olsson
Nine Psychological Tests Ulf H. Olsson
Alternative Estimators • Assuming multivariate normality • ML • GLS • ULS • If the model holds, ML and GLS are asymptotically equivalente Ulf H. Olsson
Alternative Estimators S: sample covariance θ: parameter vector σ(θ): model implied covariance Ulf H. Olsson
Alternative Estimators Ulf H. Olsson
Alternative Estimators Ulf H. Olsson
Alternative Estimators Ulf H. Olsson
Assignment 1 • The Country/People Image • 12 items was used for the country-people Image: • For each item a 7-point semantic differential scale was used • 1)Role in world politics • 2)Refined taste • 3)Likable • 4)Trustworthy • 5)Industrious • 6)Managing the economy well • 7)Technological level • 8)Ability to handle large and complex projects • 9)Would like closer ties • 10)Educational level • 11)Polluted environment • 12)Athletic People • Research project: • Use the file CI-week11.psf to find a factor structure for the Construct Country Image. Test and evaluate the model. Ulf H. Olsson
Assignment 2 • Political Efficacy • Campel et al. (1954): Political Efficacy is the feeling that individual political action does have, or can have, an impact upon political process. • Observed (measured) variables: • NOSAY: People like me have “no say” in what the government does • VOTING: Voting is the only way that people like me can have “any say” about how • the government runs things. • COMPLEX: Sometimes politics and government seem so complicated that a person like me cannot really understand what is going on • NOCARE: I don’t think that public officials care much about what people like me think • TOUCH: Generally speaking, those we elect to Parliament lose touch with people pretty quickly • INTEREST: Parties are only interested in people’s votes but not in their opinions • Use the data set in the file: Efficacy2005.psf and find a suitable factor model Ulf H. Olsson