R Language Time Series and Forecasting Exploratory Data Analysis with time-series data
Example
data(AirPassengers)
class(AirPassengers)
1 "ts"
In the spirit of Exploratory Data Analysis (EDA) a good first step is to look at a plot of your time-series data:
plot(AirPassengers) # plot the raw data
abline(reg=lm(AirPassengers~time(AirPassengers))) # fit a trend line
For further EDA we examine cycles across years:
cycle(AirPassengers)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 1949 1 2 3 4 5 6 7 8 9 10 11 12 1950 1 2 3 4 5 6 7 8 9 10 11 12 1951 1 2 3 4 5 6 7 8 9 10 11 12 1952 1 2 3 4 5 6 7 8 9 10 11 12 1953 1 2 3 4 5 6 7 8 9 10 11 12 1954 1 2 3 4 5 6 7 8 9 10 11 12 1955 1 2 3 4 5 6 7 8 9 10 11 12 1956 1 2 3 4 5 6 7 8 9 10 11 12 1957 1 2 3 4 5 6 7 8 9 10 11 12 1958 1 2 3 4 5 6 7 8 9 10 11 12 1959 1 2 3 4 5 6 7 8 9 10 11 12 1960 1 2 3 4 5 6 7 8 9 10 11 12
boxplot(AirPassengers~cycle(AirPassengers)) #Box plot across months to explore seasonal effects
