How many observations are sufficient for an OLS regression?

[Bright Tree]

Dear friends, How many observations are sufficient for an OLS regression? If I only had around 70 obs, was that estimation result reliable? Thanks!

[Richard Williams]

Depends on what you want to do. If you have 20 independent variables you want to analyze you are probably in trouble. The relationship between variables will have to be pretty strong for you to find much. Your confidence intervals may be very wide and your estimates imprecise.

But yes, people can and do analyze data sets with only 70 cases.

[Bright Tree]

Dear Professor Williams, thank you a lot for your help!