4. Carry out a small simulation study to investigate how quickly the sample act and pact converge to the theoretical acf and pacf for different n for a particular ARMA(1,2) model Xi-61X1= 2+021-1+ 0221-21 where ( = 0.8. 0, = -0.5,02 = -0.4 and o, = 1. and the white noise is normally distributed. Try n = 20,50, 100, 1000, 10000, and briefly comment on how close the sample and theoretical values are