Explain in detail the purpose of correlation analysis. Explain in...

1. Explain in detail the purpose of correlation analysis.
2. Explain in detail how well a multiple regression equation fits the data.
3. Explain in detail a qualitative, dummy variable in multiple regression.
4. Define and describe the components of a time series.
5. Explain in detail the difference between linear and nonlinear regression.

I need it wrote in essay.