(solution) Here are 4 short questions about econometrics, I already get some answers but some of them confused

(solution) Here are 4 short questions about econometrics, I already get some answers but some of them confused

Here are 4 short questions about econometrics, I already get some answers but some of them confused me. So please be professional, serious and specific. I will not accept roughly incorrect answers.Most of them are about time series data. See attachment, if need anything else let me know Document Preview: Q 1 Q 2 Q 3 Suppose you want to estimate the model: Q4