Hi,
I need help creating a code for a multiple BACI design (Before-After
Control-Impact) ANOVA. I'm new to R and basically need to run a
complexmixed model ANOVA that treats location as a random factor.
Data are from a fire experiment, run 2001-2004 (2 years pre, 2 years
post). Response is bird abundance. 4 Treatments had 3 replicates
each(forest stands): 1. Control, 2. Prescribed fire only, 3.
Timber harvesting
only, and 4. Fire and harvesting.
Basically, I'm having trouble figuring out the code that makes the
variable "LOC" a random factor.
Also, I'm having trouble figuring out how to script contrasts
comparingthe treatments to the control (multiple comparisons w/ a
control).
Treatment group is not a part of the lme script. Do I need to run
themeach individually, i.e. C vs. T1, C vs. T2, C vs T3? or can I
code in
treatment contrasts?
Script (used S-plus GUI to build it):
GCKI~.+C+B+LOC%in%C+T%in%B+C:B+C:T%in%B+LOC%in%C:B+LOC%in%C:T%in%B
**unsure what goes here to make LOC random****
Terms:
GCKI: Golden-crowned kinglet abundance.
C: Control-Impact (2 levels, either control (no treatment), or impact
(received treatment after 2 years)
B: Before-After (2 levels, 2001-2002 = Before, 2003-2004 = After)
T: Time, 4 levels, years 2001, 2002, 2003, 2004
LOC: location, 3 replicates in among the 4 treatments (RANDOM FACTOR)
Sorry to write so much, but any help would be appreciated. The ANOVA
model comes from a book: Monitoring Ecological Impacts: Downes et al.
2002.
I am used to running GUIs, but it appears I need to script this
ANOVA. I
am unfamiliar with random factor scripts or scripts for multiple
contrastswith controls.
Cheers,
Andrew