# Analysis of Variance and Covariance

## Online Workshops

## Free Webinar Recordings

- Fixed and Random Factors in Mixed Models: What IS the difference?
- The 13 Steps to Running Any Statistical Model
- Effect Size Statistics

## Articles at The Analysis Factor

- 3 Mistakes Data Analysts Make in Testing Assumptions in GLM
- 3 Reasons Psychology Researchers should Learn Regression
- 3 Situations when it makes sense to Categorize a Continuous Predictor in a Regression Model
- 7 Practical Guidelines for Accurate Statistical Model Building
- A Comparison of Effect Size Statistics
- About Dummy Variables in SPSS Analysis
- Actually, you can interpret some main effects in the presence of an interaction
- Analyzing Pre-Post Data with Repeated Measures or ANCOVA
- Anatomy of a Normal Probability Plot
- ANCOVA Assumptions: When Slopes are Unequal
- Approaches to Repeated Measures Data: Repeated Measures ANOVA, Marginal, and Mixed Models
- April 2013 Member Webinar: Hierarchical Regressions
- Assumptions of Linear Models are about Residuals, not the Response Variable
- Beyond Median Splits: Meaningful Cut Points
- Can Likert Scale Data ever be Continuous?
- Checking Assumptions in ANOVA and Linear Regression Models: The Distribution of Dependent Variables
- Checking the Normality Assumption for an ANOVA Model
- Concepts in Linear Regression you need to know before learning Multilevel Models
- Confusing Statistical Term #6: Factor
- Confusing Statistical Term #7: GLM
- Confusing Statistical Terms #1: The Many Names of Independent Variables
- Confusing Statistical Terms #3: Levels of a Factor in Multilevel Models Measured at a Nominal Level
- Confusing Statistical Terms #5: Covariate
- Continuous and Categorical Variables: The Trouble with Median Splits
- December 2013 Member Webinar: Interactions in ANOVA and Regression Models, Part 1
- Dummy Coding in SPSS GLM–More on Fixed Factors, Covariates, and Reference Groups, Part 1
- Dummy Coding in SPSS GLM–More on Fixed Factors, Covariates, and Reference Groups, Part 2
- February 2013 Member Webinar: Types of Regression Models and When to Use Them
- Five Advantages of Running Repeated Measures ANOVA as a Mixed Model
- Five Extensions of the General Linear Model
- GLM in SPSS: Centering a Covariate to Improve Interpretability
- Have you Wondered how using SPSS Burns Calories?
- How Simple Should a Model Be? The Case of Insignificant Controls, Interactions, and Covariance Structures
- How to Calculate Effect Size Statistics
- Interpreting (Even Tricky) Regression Coefficients – A Quiz
- Interpreting Interactions Between Two Effect-Coded Categorical Predictors
- Interpreting Interactions when Main Effects are Not Significant
- Interpreting Interactions: When the F test and the Simple Effects disagree.
- January 2014 Member Webinar: Interactions in ANOVA and Regression Models, Part 2
- January 2015 Member Webinar: ANCOVA (Analysis of Covariance)
- July 2017 Member Webinar: The Multi-Faceted World of Residuals
- June 2013 Member Webinar: MANOVA
- June 2014 Member Webinar: Multiple Comparisons
- Linear Mixed Models for Missing Data in Pre-Post Studies
- May 2013 Member Webinar: Using Excel to Graph Predicted Values from Regression Models
- Model Building Strategies: Step Up and Top Down
- New version released of Amelia II: A Program for Missing Data
- Non-parametric ANOVA in SPSS
- One-tailed and two-tailed tests
- Problems Caused by Categorizing Continuous Variables
- Six Differences Between Repeated Measures ANOVA and Linear Mixed Models
- Specifying Fixed and Random Factors in Mixed Models
- Specifying Variables as Within-Subjects Factors in Repeated Measures
- Spotlight Analysis for Interpreting Interactions
- SPSS GLM: Choosing Fixed Factors and Covariates
- Steps to Take When Your Regression (or Other Statistical) Results Just Look…Wrong
- Testing and Dropping Interaction Terms in Regression and ANOVA models
- The 13 Steps for Statistical Modeling in any Regression or ANOVA
- The 3 Stages of Mastering Statistical Analysis
- The Assumptions of Linear Models: Explicit and Implicit
- The Difference Between Clustered, Longitudinal, and Repeated Measures Data
- The Difference Between Crossed and Nested Factors
- The Difference Between Eta Squared and Partial Eta Squared
- The Difference Between Interaction and Association
- The General Linear Model, Analysis of Covariance, and How ANOVA and Linear Regression Really are the Same Model Wearing Different Clothes
- The Problem with Using Tests for Statistical Assumptions
- The Repeated and Random Statements in Mixed Models for Repeated Measures
- The Wide and Long Data Format for Repeated Measures Data
- Using Adjusted Means to Interpret Moderators in Analysis of Covariance
- What Is Regression to the Mean?
- Whatâ€™s in a Name? Moderation and Interaction, Independent and Predictor Variables
- When Assumptions of ANCOVA are Irrelevant
- When Dependent Variables Are Not Fit for Linear Models, Now What?
- When Does Repeated Measures ANOVA not work for Repeated Measures Data?
- When Dummy Codes are Backwards, Your Stat Software may be Messing With You
- When to Check Model Assumptions
- When to leave insignificant effects in a model
- When Unequal Sample Sizes Are and Are NOT a Problem in ANOVA
- Why ANOVA and Linear Regression are the Same Analysis
- Why ANOVA is Really a Linear Regression, Despite the Difference in Notation
- Why report estimated marginal means in SPSS GLM?