Exercise 7.3c: Questions

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1. Which method, least squares or least absolute deviations, is more robust? That is, which method is more resistant to vertical changes in the data values?

2. Which method, the least squares method or least absolute deviations method, seems to be more unstable? That is, which line can jump large amounts as data points are moved horizontally?

3. Take this quiz to see if you can tell the difference between least absolute deviations (LAD) fitting and least squares (LS) fitting.

PLOT 1: LAD line, PLOT 2: LS line
PLOT 1: LS line, PLOT 2: LAD line

Please explain your choice for question 3.