December 2, 2019
Lecturer: Paul Williamson
Variance = sum of squared errors Standard Deviation = square root of variance
Principles of Table Design
- never present raw output
- rates are usually better than counts
- but show number of persons that equals 100%
- make tables interesting:
- compare subgroups
- shading scheme must be unambiguous for ranked categories
- only use pie charts in graph multiples
- be imaginative
- maximize data:ink
- provide a context
- table or graph – not both
- captions: above tables, below figures
- attribute contents
Measurement Error & Missing Data
- Systematic bias.
- Random bias.
Either impute plausible values or delete missing values.
‘Conditional Independence Assumption’.
Inferential Statistics and χ-Squared
- Statistical Significance is an arbitrary threshold.
- Statistical Significance is not equivalent to ‘Importance’.
- ‘Effect size’ more important that ‘p-value’.
- Publish all findings (even if not statistically significant).
Correlation and Regression
Best line minimizes sum of squared errors.
Visualizing correlation: - for continuous, scatter plot - for categorical, stacked percentage bar charts
- Meets Regression Assumptions?
- Statistically robust?
- Best model?
Dangers of Area-Level Data Analysis
- Ecological Fallacy
- Modifiable Areal Unit Problem
- Scale Effects