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## Chapter 17

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**Chapter 17**Making Sense of Advanced Statistical Procedures in Research Articles**Brief Review of Multiple Regression**• Predicting scores on a criterion variable from two or more predictor variables • Proportion of variance accounted for (R2)**Hierarchical and Stepwise Multiple Regression**• Hierarchical multiple regression • Examine contribution to the prediction of each variable added in a sequential fashion • Stepwise Multiple regression • Controversial exploratory procedure • Predictor variable with best prediction located • Find next predictor variable that gives highest R2with first predictor variable • Repeat until best predictor variable does not give significant improvement**Hierarchical and Stepwise Multiple Regression**• Both involve adding variables a stage at a time and checking for significant improvement of prediction • Theory/plan determines order of variables in hierarchical regression • No initial plan in stepwise regression • Useful in exploratory and applied research**Partial Correlation**• Association between two variables, over and above influence of one or more other variables • Holding constant, partialing out, controlling for, adjusting for • Partial correlation coefficient**Reliability**• Reliability • Test-retest reliability • Split-half reliability • Cronbach’s alpha (α) • Interrater reliability**Factor Analysis**• Measured large number of variables • Identifies variables that clump together • Factor • Factor loading • Several approaches to factor analysis • Naming the factors**Causal Modeling**• Measured large number of variables • Does the pattern of correlations match theory of which variables cause which? • Path analysis • Path • Path coefficient**Causal Modeling**• Path analysis**Causal Modeling**• Structural equation modeling • Elaboration of path analysis • Fit index • e.g., RMSEA • Latent variable • Measured variable**Causal Modeling**• Structural equation modeling**Causal Modeling**• Structural equation modeling**Causal Modeling**• Limitations • Other patterns of causality possible • Alternative theories • Correlation and causality • Linear relationships • Restriction in range**Independent and Dependent Variables**• Independent variable • Predictor variable • Dependent variable • Criterion variable**Analysis of Covariance (ANCOVA)**• ANOVA adjusting the dependent variable for effect of additional variables • Analogous to partial correlation • Covariate • Adjusted means**Multivariate Analysis of Variance (MANOVA) and Covariance**(MANCOVA) • Multivariate statistics • More than one dependent variable • Multivariate analysis of variance (MANOVA) • ANOVA with more than one dependent variable • Univariate ANOVA**Multivariate Analysis of Variance (MANOVA) and Covariance**(MANCOVA) • Multivariate analysis of covariance (MANCOVA) • ANCOVA with more than one dependent variable • MANOVA with covariates**Controversy: Should Statistics be Controversial?**• Fisher • Neyman • Pearson**Reading Results Using Unfamiliar Techniques**• Don’t panic! • Look for a p level • Look for pattern of results that is considered significant • Look for degree of association or size of the difference • Look up in statistics book • Take more statistics courses!