beav2 | R Documentation |
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.
beav2
The beav2
data frame has 100 rows and 4 columns.
This data frame contains the following columns:
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 Celsius.
activ
Indicator of activity outside the retreat.
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.
Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.
beav1
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) # for gls and corAR1 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)