Final answer:
In the presence of correlated observations, the OLS estimators are unbiased, but their estimated standard errors are inappropriate. This can lead to the model looking better than it really is, the F test suggesting significance when it's not true, and the t test also suggesting significance when it's not true.
Step-by-step explanation:
When there are correlated observations, the OLS estimators are unbiased but their estimated standard errors are inappropriate. This can lead to several consequences:
- The model may appear better than it really is with a spuriously high R-squared value (A).
- The F test may suggest that the predictor variables are individually and jointly significant, even when this is not true (B).
- The t test may suggest that the predictor variables are individually and jointly significant, even when this is not true (D).
Therefore, the correct answer is C: All of the answers are correct.