spruce {geepack} | R Documentation |
The spruce
data frame has 1027 rows and 6 columns. The data
consists of measurements on 79 sitka spruce trees over two growing
seasons. The trees were grown in four controlled environment chambers,
of which the first two, containing 27 trees each, were treated with
introduced ozone at 70 ppb whilst the remaining two, containing 12 and
13 trees, were controls.
data(spruce)
This data frame contains the following columns:
enriched
and normal
Diggle, P.J., Liang, K.Y., and Zeger, S.L. (1994) Analysis of Longitudinal Data, Clarendon Press.
data(spruce) spruce$contr <- ifelse(spruce$ozone=="enriched", 0, 1) sitka88 <- spruce[spruce$wave <= 5,] sitka89 <- spruce[spruce$wave > 5,] fit.88 <- geese(logsize ~ as.factor(wave) + contr + I(time/100*contr) - 1, id=id, data=sitka88, corstr="ar1") summary(fit.88) fit.89 <- geese(logsize ~ as.factor(wave) + contr - 1, id=id, data=sitka89, corstr="ar1") summary(fit.89)