A simple question.
When people talk about "the least square estimator", what is this estimator?
Is it an unbiased estimator of the slope of the regression line?
In a paper I'm reading, Let's Take the Con Out of Econometrics, the author writes
Randomization implies that the least squares estimator is "unbiased," but that definitely does not mean that for each sample the estimate is correct. (pg 31, last par)
I understand the second half of the sentence, but I don't understand why "randomization implies that the least squares estimator is 'unbiased.'" I do know that an estimator is unbiased if the expectation of the estimator is equal to the true value of the parameter.
Note: I get the impression that cross validated is for more professional statisticians, not for undergraduate level questions, hence I am posting on this site where I have seen more undergraduate level questions. Is that accurate?