WEEK 5: Understanding Multiple Regression Analysis
Multiple Regression Analysis Assignment
Overview
In this assignment, you will explore how different health factors influence healthcare utilization using multiple regression analysis. You will work with a dataset containing information about doctor visits, physical health, mental health, and stress levels.
Dataset Information
The file (regress.sav/regress.csv) contains the following variables:
- timedrs: Number of visits to health professionals
- phyheal: Number of physical health symptoms
- menheal: Number of mental health symptoms
- stress: Stressful life events score
Part 1: Data Exploration (20 points)
Begin by examining relationships in your data:
- Create visualizations showing the relationships between doctor visits and each predictor
- Examine potential univariate and bivariate outliers
- Document any concerning patterns and how you would handle them
- Note: For consistency, keep all data points in your analysis even if you identify outliers
- Calculate and interpret the correlations between variables
Part 2: Standard Multiple Regression (40 points)
Conduct a standard multiple regression analysis using either SPSS or Jamovi:
If Using SPSS:
- Navigate to ANALYZE → REGRESSION → LINEAR
- Set timedrs as your dependent variable
- Enter all other variables as independent variables
- Request part and partial correlations in the Statistics menu
If Using Jamovi:
- Go to ANALYSES → REGRESSION → LINEAR REGRESSION
- Set timedrs as your dependent variable
- Move all other variables to the covariates box
- Request model fit measures and coefficient statistics
- For part and partial correlations:
- Use REGRESSION → PARTIAL CORRELATION
- You’ll need separate analyses for each predictor (detailed instructions below)
Required Output:
- Overall model fit (R, R², adjusted R²)
- ANOVA results
- Coefficients with significance tests
- Part and partial correlations
- At least one visualization supporting your analysis
Part 3: Hierarchical Regression (40 points)
Conduct a hierarchical regression analysis:
- Determine a theoretically-justified order for entering your predictors
- Document your reasoning for this order
- Enter variables in sequence, examining changes at each step
Required Analysis:
- R² change at each step
- Significance of each change
- Final model coefficients
- Comparison with standard regression results
Write-up Requirements
Your results section should include:
- Data Screening (15%)
- Description of distributions
- Discussion of any outliers or patterns
- Bivariate relationship summaries
- Standard Regression Results (40%)
- Overall model evaluation
- Individual predictor contributions
- Effect size interpretations
- Practical significance discussion
- Hierarchical Regression Results (30%)
- Justification for variable order
- Changes at each step
- Final model interpretation
- Visual Presentation (15%)
- Relevant plots/figures
- Properly formatted tables
- Clear labeling and titles
Appendix: Understanding Partial and Semi-partial Correlations in Jamovi
Overview
While SPSS provides partial and semi-partial correlations with a single checkbox, Jamovi requires a more detailed approach that can actually deepen your understanding of these concepts.
Conceptual Understanding
- Partial correlation: Shows the relationship between two variables after controlling for other variables
- Semi-partial (part) correlation: Shows the unique contribution of a predictor to the dependent variable
Getting These Values in Jamovi
- For each predictor, you’ll need to run a separate analysis:
- Go to ANALYSES → REGRESSION → PARTIAL CORRELATION
- Under “Correlation Type” select “Semipartial”
- You don’t need to check “Report significance”
- For each analysis:
- Variables box: Put timedrs and one predictor
- Control Variables box: Put the other two predictors
- Running Three Analyses: Example for phyheal:
- Variables: timedrs and phyheal
- Control Variables: menheal and stress
Repeat this process for menheal and stress.
Interpreting Results
- The coefficient in the output is your semi-partial correlation
- Square this value to get the unique variance explained
- Compare these values to understand each predictor’s unique contribution
Example Interpretation
“The semi-partial correlation between physical health and doctor visits, controlling for mental health and



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