This is the test set of the toy time series data, i.e. the last 2000
of the total 3000 observations.
The data follow a second order AR model. The first order
coefficient is -0.5 and the second order coefficient
0.3.
Use file.show(system.file("toyDataSrc", "sisalToyTs.R",
package="sisal")) to view the script that generated the data.