Econometrics Lecture: OLS Unbiased Proof

Part 1 of the "Gauss-Markov" Theorem proof, in which we walk through applying the CLRM assumptions to show that Ordinary Least Squares will provide an unbiased estimator (using summation notation, rather than matrices). The Classical Assumptions: https://youtu.be/9iOAbZxX4z8 Link to the excellent Introduction to Econometrics Textbook by AH Studenmund: https://www.amazon.com/gp/product/9332584915/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=9332584915&linkCode=as2&tag=mikejonasecon-20&linkId=6697afcfde8c335b461795eec22e3977