Problem 1

Obtain monthly data for Consumer Price Index for All Urban Consumers: All Items, Not Seasonally Adjusted FRED/CPIAUCNS. Use it to construct the time series for month-over-month inflation rate, yt = ∆logCPIt.

(a) Restrict the sample to 1955M1-2013M12. Plot the time series for inflation yt.

(b) Set up and estimate local level model with seasonal component.

## , , 1
## 
##             level sea_dummy1 sea_dummy2 sea_dummy3 sea_dummy4 sea_dummy5
## level           1          0          0          0          0          0
## sea_dummy1      0         -1         -1         -1         -1         -1
## sea_dummy2      0          1          0          0          0          0
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## sea_dummy10     0          0          0          0          0          0
## sea_dummy11     0          0          0          0          0          0
##             sea_dummy6 sea_dummy7 sea_dummy8 sea_dummy9 sea_dummy10
## level                0          0          0          0           0
## sea_dummy1          -1         -1         -1         -1          -1
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## sea_dummy5           0          0          0          0           0
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## sea_dummy7           1          0          0          0           0
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## level                 0
## sea_dummy1           -1
## sea_dummy2            0
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## sea_dummy4            0
## sea_dummy5            0
## sea_dummy6            0
## sea_dummy7            0
## sea_dummy8            0
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## sea_dummy10           0
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## , , 1
## 
##             [,1] [,2]
## level          1    0
## sea_dummy1     0    1
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## sea_dummy3     0    0
## sea_dummy4     0    0
## sea_dummy5     0    0
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## sea_dummy10    0    0
## sea_dummy11    0    0
## , , 1
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##      level sea_dummy1 sea_dummy2 sea_dummy3 sea_dummy4 sea_dummy5
## [1,]     1          1          0          0          0          0
##      sea_dummy6 sea_dummy7 sea_dummy8 sea_dummy9 sea_dummy10 sea_dummy11
## [1,]          0          0          0          0           0           0
## , , 1
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##      [,1] [,2]
## [1,]   NA    0
## [2,]    0   NA
## , , 1
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##      [,1]
## [1,]   NA
## [1] -5.845752 -7.532564 -2.925709
## , , 1
## 
##            [,1]         [,2]
## [1,] 0.00289216 0.0000000000
## [2,] 0.00000000 0.0005353639
## , , 1
## 
##            [,1]
## [1,] 0.05362667
##  [1] "level"       "sea_dummy1"  "sea_dummy2"  "sea_dummy3"  "sea_dummy4" 
##  [6] "sea_dummy5"  "sea_dummy6"  "sea_dummy7"  "sea_dummy8"  "sea_dummy9" 
## [11] "sea_dummy10" "sea_dummy11"

(c) Plot the smoothed level and smoothed seasonal components μt|T and γt|T together with their 90% confidence intervals. Plot the smoothed irregular component εt|T.

(d) Create a 36 period ahead forecast i.e. a forecast for period 2014M1-2016M12. Plot the forecast together with 90% confidence intervals and actual data for the period 2005M1-2016M12. How well does the model perform when it comes to its forecasting ability?

Based on the below plot, I feel like the forecast does a resonable good job at predicting month-over-month inflation. At every point, the actual data seems to be contained within the 90% ci for the forecasted portion of the model.