Data analysis - unemployment II
Now, you will continue fitting an SARIMA model to the monthly US unemployment unemp time series by looking at the sample ACF and PACF of the fully differenced series.
Note that the lag axis in the sample P/ACF plot is in terms of years. Thus, lags 1, 2, 3, … represent 1 year (12 months), 2 years (24 months), 3 years (36 months), …
Once again, the astsa package has been pre-loaded for you.
Bu egzersiz
ARIMA Models in R
kursunun bir parçasıdırEgzersiz talimatları
- Difference the data fully (as in the previous exercise) and plot the sample ACF and PACF of the transformed data to lag 60 months (5 years). Consider that, for
- the nonseasonal component: the PACF cuts off at lag 2 and the ACF tails off.
- the seasonal component: the ACF cuts off at lag 12 and the PACF tails off at lags 12, 24, 36, …
- Suggest and fit a model using
sarima(). Check the residuals to ensure appropriate model fit.
Uygulamalı interaktif egzersiz
Bu örnek kodu tamamlayarak bu egzersizi bitirin.
# Plot P/ACF pair of fully differenced data to lag 60
dd_unemp <- diff(diff(unemp), lag = 12)
# Fit an appropriate model