## Session 4: Regression Modeling (Qualitative Data); Outliers

- Qualitative variables
  - Representation via "dummy" variables
  - Soccer attendance: An analysis of variance example

- Structural variations (3) [optional]

- Logarithmic transformations

- NBA salaries

- Residual analysis

  - Recognizing and dealing with outliers
  - More on the McDonalds "Monopoly" scandal

- Summary: Modeling
- Session slides

- Sample exam

- Unique Unicycles (dataset)
- Unique Unicycles (exam)
- Unique Unicycles (answers)

- Sample exam, with tutorial

  - Optional background reading on Microsoft vs. Linux
  - "Mantis Technologies" dataset and description
  - Exam questions
  - Exam answers
  - "Mantis Technologies" Webex tutorial

  Note: About half of each exam covers basic material, and the other half consists of questions of a more challenging nature. I grade accordingly, with the "pass" line at around 50%, and the rest of the questions used to separate the high passes from the passes. (So don't panic if you aren't sure how to do a few of the problems.)