Regression: the line
Content for Thursday, March 4, 2027
Goals
By the end of this topic, you should be able to:
- Find the least squares line, and read a and b in the units of the scores
- Predict a score, and find a residual
- Say what r² means
- Explain regression to the mean
Reading
- Section 14-6, through the standard error of estimate and r².
NoteThe book and our slides
- The book: writes the line as Ŷ = bX + a, and the slope as b = r(s_Y/s_X). Our slides: write a + bX, and σ̂ for s. Same line, same numbers.