# 程序代写｜ECO 521 Quantitative Methods II Problem Set 3

## 这是一篇来自美国Spring Semester 2023的关于编写的SAS程序的副本，输出和任何相关图表，当然还有您对问题的分析和解决方案的程序代写

These problems are due by the beginning of class, Wednesday, March 29, 2023. No exceptions! You should submit a copy of the SAS program you wrote in order to solve the problem, the output and any relevant charts, and of course your analysis of and solution to the problem.

Please follow the specifications for submitting the problems (posted separately). Failure to do so will result in a 10 percent penalty on the problem set. I reserve the right to escalate the penalty on future problem sets if you insist on failing to adhere to the specifications.

late problem sets will not be accepted!

1. Once again, the Excel workbook on Blackboard contains three real-world time series data sets. The last worksheet of the workbook has a short data dictionary.

A.Use SAS to plot each original data series before proceeding to the next phase of analysis. State your impressions of each series before doing any identification or modeling attempts. This may include whether or not to apply a pre-differencing transformation.

B.Use SAS to obtain the SACF and SPACF for each series and tentatively identify a time series model for each series. You must decide on one model — you may not hedge your bets! If you insist on selecting multiple models, I will take the first identification you make as your solution and will ignore the rest.

C.Detach the last 10 percent of the observations for each series. Use SAS to estimate the model that you identified using the “trimmed” data set. Discuss (based on the SAS output) how well you were able to identify the model.

D.Use your model to forecast the observations you deleted from the full data set. (Of course, the number of forecasts should match the number of observations in your holdout set.) Compute the RMSE for the forecast.

E.Use one of the naive forecasting methods to compute a pseudo out-of-sample forecast and find the RMSE for the naive forecast. Explain why you selected your naive model.

Compare the RMSE from the naive forecast with that from the Box-Jenkins model. Which forecasting method worked better? Note: Of course, you are doing a naive forecast for each series.

F.Finally, plot the actuals, fits, confidence band and forecast for each ARIMA forecast.

Do not include the naive forecast in the plot.