\HeaderA{beav2}{Body Temperature Series of Beaver 2}{beav2}
\keyword{datasets}{beav2}
\begin{Description}\relax
Reynolds (1994) describes a small part of a study of the long-term
temperature dynamics of beaver \emph{Castor canadensis} in
north-central Wisconsin.  Body temperature was measured by telemetry
every 10 minutes for four females, but data from a one period of less
than a day for each of two animals is used there.
\end{Description}
\begin{Usage}
\begin{verbatim}
beav2
\end{verbatim}
\end{Usage}
\begin{Format}\relax
The \code{beav2} data frame has 100 rows and 4 columns.
This data frame contains the following columns:
\describe{
\item[\code{day}] Day of observation (in days since the beginning of 1990),
November 3--4.

\item[\code{time}] Time of observation, in the form \code{0330} for 3.30am.

\item[\code{temp}] Measured body temperature in degrees Celsius.

\item[\code{activ}] Indicator of activity outside the retreat.

}
\end{Format}
\begin{Source}\relax
P. S. Reynolds (1994) Time-series analyses of beaver body temperatures.
Chapter 11 of
Lange, N., Ryan, L., Billard, L., Brillinger, D., Conquest, L.
and Greenhouse, J. eds (1994)
\emph{Case Studies in Biometry.} New York: John Wiley and Sons.
\end{Source}
\begin{References}\relax
Venables, W. N. and Ripley, B. D. (2002)
\emph{Modern Applied Statistics with S.} Fourth edition.  Springer.
\end{References}
\begin{SeeAlso}\relax
\code{\LinkA{beav1}{beav1}}
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
attach(beav2)
beav2$hours <- 24*(day-307) + trunc(time/100) + (time%%100)/60
plot(beav2$hours, beav2$temp, type = "l", xlab = "time",
   ylab = "temperature", main = "Beaver 2")
usr <- par("usr"); usr[3:4] <- c(-0.2, 8); par(usr = usr)
lines(beav2$hours, beav2$activ, type = "s", lty = 2)

temp <- ts(temp, start = 8+2/3, frequency = 6)
activ <- ts(activ, start = 8+2/3, frequency = 6)
acf(temp[activ == 0]); acf(temp[activ == 1]) # also look at PACFs
ar(temp[activ == 0]); ar(temp[activ == 1])

arima(temp, order = c(1,0,0), xreg = activ)
dreg <- cbind(sin = sin(2*pi*beav2$hours/24), cos = cos(2*pi*beav2$hours/24))
arima(temp, order = c(1,0,0), xreg = cbind(active=activ, dreg))

library(nlme)
beav2.gls <- gls(temp ~ activ, data = beav2, corr = corAR1(0.8),
                 method = "ML")
summary(beav2.gls)
summary(update(beav2.gls, subset = 6:100))
detach("beav2"); rm(temp, activ)
\end{ExampleCode}
\end{Examples}

