Solution
David answered on
Dec 23 2021
Introduction
Energy is everything in modern world.
Given our technology dependency, which is driven by energy coming from raw resources like coal,
petroleum etc., it’s quite obvious that we are totally dependent on these resources. But, given that
these are natural resources, and the fact that it takes thousands of year for a coal mine or a
petroleum reserve to get formed, this ever increasing dependency is creating a havoc upon the
availability of these resources.
It’s now a known fact that in about hundreds of years all these natural resources will not be
available anymore. So, it is in our prerogative to see how best we can utilize what we have right
now.
We have a monthly dataset containing historical (Jan, 1984 –Dec, 2012). data on volume of
petroleum consumed by the residential sector in the US. If, using this data, we can forecast the
future petroleum consumption, then it will surely help the government policy making, who, armed
with the forecast, can start planning on optimizing the energy resource utilization or maybe even
start planning on moving onto alternative means of energy production to cater to the increasing
demand.
Materials and Methods
The data is shown below as a time series. As we can see, there is a distinct pattern in the data, which
tells us that the variation is not all random noise and we should be able to explain a large portion of
it.
Clearly, the data is periodic, and at least after 2000, follows a downward trend. To compute the
period we take the help of a periodogram (and a smoothed periodogram) which shows that the
period is 12 months, which means that there is an annual cycle in petroleum consumption and it
has peals in year end and start of the year and touched the bottom at around mid-year.
It shows that the petroleum consumption is highest in winters.
This shows that the data can be very well represented in an ARIMA (autoregressive integrated
moving average ) framework which is defined below.
A nonseasonal ARIMA model is classified as an "ARIMA(p,d,q)" model, where:
ï‚· p is the number of autoregressive terms,
ï‚· d is the number of nonseasonal...