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.
beav1 data frame has 114 rows and 4 columns.
This data frame contains the following columns:
Day of observation (in days since the beginning of 1990), December 12–13.
Time of observation, in the form
0330 for 3.30am.
Measured body temperature in degrees Celsius.
Indicator of activity outside the retreat.
The observation at 22:20 is missing.
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 <- within(beav1, hours <- 24*(day-346) + trunc(time/100) + (time%%100)/60) plot(beav1$hours, beav1$temp, type="l", xlab="time", ylab="temperature", main="Beaver 1") usr <- par("usr"); usr[3:4] <- c(-0.2, 8); par(usr=usr) lines(beav1$hours, beav1$activ, type="s", lty=2) temp <- ts(c(beav1$temp[1:82], NA, beav1$temp[83:114]), start = 9.5, frequency = 6) activ <- ts(c(beav1$activ[1:82], NA, beav1$activ[83:114]), start = 9.5, frequency = 6) acf(temp[1:53]) acf(temp[1:53], type = "partial") ar(temp[1:53]) act <- c(rep(0, 10), activ) X <- cbind(1, act = act[11:125], act1 = act[10:124], act2 = act[9:123], act3 = act[8:122]) alpha <- 0.80 stemp <- as.vector(temp - alpha*lag(temp, -1)) sX <- X[-1, ] - alpha * X[-115,] beav1.ls <- lm(stemp ~ -1 + sX, na.action = na.omit) summary(beav1.ls, cor = FALSE) rm(temp, activ)