| beav2(MASS) | R Documentation |
The beav2 data frame has 100 rows and 4 columns on body
temperature measurements at 10 minute intervals.
day |
Day of observation (in days since the beginning of 1990), November 3-4. |
time |
Time of observation, in the form 0330 for 3.30am
|
temp |
Measured body temperature in degrees Celcius |
activ |
Indicator of activity outside the retreat |
Reynolds (1994) describes a small part of a study of the long-term temperature dynamics of beaver 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.
This data frame contains the following columns:
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) Case Studies in Biometry. New York: John Wiley and Sons.
library(ts)
data(beav2)
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$activ, type="s", lty=2)
temp <- ts(temp, start=8+2/3, frequency=6)
activ <- ts(activ, start=8+2/3, frequency=6)
acf(temp[activ==0]); acf(temp[activ==1]) # also look at PACFs
ar(temp[activ==0]); ar(temp[activ==1])
arima0(temp, order=c(1,0,0))
arima0(temp, order=c(1,0,0), xreg=activ)
dreg <- cbind(sin=sin(2*pi*beav2$hours/24), cos=cos(2*pi*beav2$hours/24))
arima0(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)