- Administrivia:
- Handout sample exam from last year
- It covers about up to here. We will have some multiple regression on the exam also.
- Exam a week from Thursday
- 2nd Homework due 2 weeks from Today

- Basic idea
- X --> Z, Z --> Y, Z --> Y looks like X --> Y
- Example: breast feeding --> bad water --> infant mortality
- Correct analysis finds this: regress Y on both X and Z
- Relationship between X and Y is marginal slope
- Relationship between X and Y HOLDING Z FIXED is partial slope
- Partial slopes are better!

- Example:
- Y = beta
_{0}+ beta_{1}X_{1}+ beta_{2}X_{2}+ error - GP1000M = 11.7 + .0089 Weight + .088 Horsepower + error
- GP1000M = 9.43 + .0136 Weight + error
- HP = Weight / 20 + error
- explination: GP1000M = 9.43 + .0089 weight + .088 * (weight/20)

- Y = beta
- Handout on Effort and Reward in College

Last modified: Tue Feb 22 13:13:26 2000