Answer true or false, and explain your answer.
The sample average is always equal to the expectation of a random variable.
When the variance of a random variable is very low, then the mean provides a good summary of the random variable. The next statements refer to the SLR model yi = β0 + β1xi + ui.
Under the Key assumption, if corr(X,Y) is not equal to 0, then a change in X affects Y because β1 is not equal to 0.
Let βˆ1 be the OLS estimator of β1. The R-squared equals 0 when βˆ1 = 0.