Alternatives to linear least squares regression

Individual assignment:

1. Why is linear regression needed?

2. How is it calculated?

3. What results are produced in calculation?

4. How can one interpret these results?

5. Business applications of linear regression (examples)

6. Alternatives to linear least squares regression

7. Caveats (when not to use)

The answers should be in good content (not so wordy) and on point answers will get more attention.

Requirements:

Include illustrations – from literature. Reference all sources