Internet Usage per Minute

Description

A time series of the numbers of users connected to the Internet through a server every minute.

Usage

data(WWWusage)

Format

A time series of length 100.

Source

Durbin, J. and Koopman, S. J. (2001) Time Series Analysis by State Space Methods. Oxford University Press. http://www.ssfpack.com/dkbook/

References

Makridakis, S., Wheelwright, S. C. and Hyndman, R. J. (1998) Forecasting: Methods and Applications. Wiley.

Examples

data(WWWusage)
work <- diff(WWWusage)
par(mfrow = c(2,1)); plot(WWWusage); plot(work)
## Not run: 
aics <- matrix(, 6, 6, dimnames=list(p=0:5, q=0:5))
for(q in 1:5) aics[1, 1+q] <- arima(WWWusage, c(0,1,q),
    optim.control = list(maxit = 500))$aic
for(p in 1:5)
   for(q in 0:5) aics[1+p, 1+q] <- arima(WWWusage, c(p,1,q),
       optim.control = list(maxit = 500))$aic
round(aics - min(aics, na.rm=TRUE), 2)
## End(Not run)