beav2 {MASS} | R Documentation

## Body Temperature Series of Beaver 2

### Description

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.

### Usage

    data(beav2)

### Format

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 Celcius
`activ`
  Indicator of activity outside the retreat

### Source

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.

### References

Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.

### See Also

`beav1`

### Examples

    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)

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