flowers {asuR} | R Documentation |
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.
data(flowers)
A data frame with 40 observations on the following 3 variables.
alt
high
low
flower
total
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=flower) # ## a model with two intercepts and one slope # altdiff <- rbind("high-low"=c(1,-1)) # m2 <- lm(log(flower) ~ alt + log(total), data=flower, # 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!