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 |
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 ()
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | 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!
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