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)