Using the following command: > library(T SA) > data(days) we can retrieve a data file named days in R. The data file contains accounting data from the Winegard Co. of Burlington, Iowa. The data are the number of days until Winegard receives payment for 130 consecutive orders from a particular distributor of Winegard products. (The name of the distributor must remain anonymous for confidentiality reasons.) The time series contains outliers that are quite obvious in the time series plot. a. Estimate the parameters of an ARMA(1,1) model for these data.
b. Estimate the parameters of an MA(2) model for these data. Which model is a better model for this data set?