Answers for unanswered question from Monday Review Session last week

During the Monday Review Session last week, several questions were unanswered, but here are the answers.

1. What does F ratio tell you? What does it have to do with regression?
- F ratio tells you how big the explained variance and unexplained variance
- F ratio determines whether your regression model (in the case of regression) is significantly different from the null model (zero) or not
- the significance level tells you whether your regression model is significantly different from zero or not

2. What does d.f.s. mean in lecture 6 powperpoint slide 27?
- d.f.s = degress of freedoms
- referring to slide 26 ANOVA table (SPSS output), df for "total" is equal to the sum of df for "regression" and df for "residual"

3. Do I have to know assumptions of regression now (see lecture 6 powerpoint slide 18)?
- no, don't worry about it if you don't understand it now. Sung will revisit this topic with a lecture later on in the course.