tdForm | R Documentation |
This function formulates linear time-decline formulas (ltd) from categorical variables in multilevel ecological data series.
tdForm(rd, prim.cov = FALSE, on.time = TRUE, log.t = FALSE, lev.rm = NULL)
rd |
|
prim.cov |
|
on.time |
|
log.t |
|
lev.rm |
NULL or |
the ltd formulas belong to following
general equation: log (x) = log (csx) + f(time);
where the relative organic growth (x) is
explained by the cumulative organic growth (csx)
plus a function of time f(time); with f(time)
being either the time or a logarithmic
transformation the time. The ltd can be
implemented by modelFrame
function
to subtract trends in organic MEDS
formula
with the forms: 'resp ~ cov | group' or '~ cov'.
Wilson Lara <wilarhen@gmail.com>, Felipe Bravo <fbravo@pvs.uva.es>
Zeide B. 1993. Analysis of Growth Equations. For. Sci., 39: 594-616.
## an ltd formula: lev <- c('plot','tree') tdeq <- tdForm(lev,log.t = TRUE) tdeq ## (not run) only primary covariate: tdeq1 <- tdForm(lev,prim.cov = TRUE) tdeq1 ##Multilevel data frame of tree-ring widths: data(Prings05,envir = environment()) ## removing two levels: 'plot' and 'tree' from the formula tdea2 <- tdForm(Prings05, lev.rm = c('plot','tree')) tdea2 <- tdForm(Prings05, lev.rm = 2:3)
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.