Background of linear regression
You can use linear regression for causal research, result prediction, or trend prognosis.
By using linear regression models, you can identify the strength of the effect of one or more independent variables on a dependent variable. In causal researches, for example, you can distinguish the strength of the relationship between education and income, dose and effect, advertisement and sales.
You can use linear regression models also to foretell effects or impacts of changes, that is, how much does the dependent variable change, when one or more independent variables are changed. For example, you can find out how much extra X you get for one extra unit Z.
And last but not least, you can use linear regression analysis to predict coming trends and values, for example, to predict future gold prices or future sales for a product.