flowers: Flower
In asuR: Advanced statistics using R

Description Usage Format Details Source Examples

A data set with the dry mass of all flowers and the dry mass of the total plant from 20 species growing at high and 20 species growing at low altitude.

1	data(flowers)

A data frame with 40 observations on the following 3 variables.

alt: a factor with levels high low
flower: a numeric vector; dry mass of flowers in mg
total: a numeric vector; dry mass of total plant in mg

The data sets shows a random subsample of the original data set.

Fabbro, T. & Koerner, Ch. (2004): Altitudinal differences in flower traits and reproductive allocation. FLORA 199, 70-81. Fabbro, Koerner ()

data(flowers)






## a model with two intercepts and two slopes
#  m1 <-lm(log(flower) ~ alt/log(total) -1, data=flowers)
#
## a model with two intercepts and one slope
#  altdiff <- rbind("high-low"=c(1,-1))
#  m2 <- lm(log(flower) ~ alt + log(total), data=flowers,
#           contrasts=list(alt=mycontr(contr=altdiff)))
#
## are separate slopes needed?
#  anova(m1, m2) # conclusion:
#
## no difference in slopes but difference in intercept
## for interpretation also test whether the slope is one!