Displaying 20 results from an estimated 1100 matches similar to: "problem with interaction in lmer even after creating an "interaction variable""
2012 Oct 30
2
bootstrapping quantile regression
HI everyone,
I try to get some bootstrap CIs for coefficients obtained by quantile
regression. I have influencial values and thus switched to quantreg..
The data is clustered and within clusters the variance of my DV = 0..
Is this sensible for the below data? And what about the warnings?
Thanks in advance for any guidance,
Kay
> dput(d)
structure(list(Porenfläche = c(4990L, 7002L, 7558L,
2005 Nov 10
2
IF/Else
Hi,
I am trying to write a for loop with if else statements to calculate
biomass density estimates for different types of sampling gear.
My code is:
bmd=for (i in 1:length(Gear)){
if (Gear==20) {bioden=Biomass/141}
else {if (Gear==23) {bioden=Biomass/68}}
else {if (Gear==160) {bioden=Biomass/4120}}
else {if (Gear==170) {bioden=Biomass/2210}}
else {if (Gear==300)
2011 Feb 06
1
anova() interpretation and error message
Hi there,
I have a data frame as listed below:
> Ca.P.Biomass.A
P Biomass
1 334.5567 0.2870000
2 737.5400 0.5713333
3 894.5300 0.6393333
4 782.3800 0.5836667
5 857.5900 0.6003333
6 829.2700 0.5883333
I have fit the data using logistic, Michaelis?Menten, and linear model,
they all give significance.
> fm1 <- nls(Biomass~SSlogis(P, phi1, phi2, phi3), data=Ca.P.Biomass.A)
2012 Feb 03
1
ordering of factor levels in regression changes result
I was surprised to find that just changing the base level of a factor variable changed the number of significant coefficients in the solution.
I was surprised at this and want to know how I should choose the order of the factors, if the order affects the result.
Here is the small example. It is taken from 'The R Book', Crawley p. 365.
The data is at
2011 Apr 13
1
print to .jpeg
Evening folks,
I'm trying to print a series of graphs to .jpeg using a variable as the
title, but run into the difficultly that I can't find a way to append the
file extension to the .jpeg (in this case extensionless!) files.
Example:
----
species.name="CussoniaHolstii"
dia<-10:100
biomass = -21.4863 + 0.5797 * (dia ^ 2)
biomass
jpeg(species.name)
plot (biomass,
2012 Sep 14
1
linear mixed-effects models with two random variables?
Dear R users,
Does anyone knows how to run a glmm with one fixed factor and 2 random
numeric variables (indices)? Is there any way to force in the model a
separate interaction of those random variables with the fixed one?
I hope you can help me.
#eg.
Reserve <- rep(c("In","Out"), 100)
fReserve <- factor(Reserve)
DivBoulders <- rep
2008 Feb 21
1
update don't find an object
Hi,
I have a situation here.
I try this update:
mmaa <- update(mma,biomass~qvartemp)
but I have this message:
Error in eval(expr, envir, enclos) : object "qvartemp" not found
but this object exist:
[1] "cont" "i" "levelsord" "mma" "qvar" "qvarmma"
[7] "qvartemp" "test"
2017 Jun 21
0
Help/ Mathematics
Hi Ahmed,
Your problem appears trivial as you have already specified the form of
the calculation.
Learn how to "extract" specified elements from a data structure:
# first value
sum(dataset1$NPP[dataset1$date >= date1 &
dataset1$date <= date2])
# second value
dataset2$biomass[dataset2$date == date2] -
dataset2$biomass[dataset2$date == date1]
# third value
2011 Apr 20
3
succession time series graph
Dear gracious R community,
I would like to produce charts of phytoplankton biomass changes
through time. Each species has a line, and the biomass varies in
mirror form along the line for each species along the X time axis.
Here is an example of what I'd like to do:
http://www.er.uqam.ca/nobel/r30240/Succession.jpg
Any suggestions?
Thanks
David Bird
UQAM, Montreal
2009 Jul 23
1
simple lme question
Hi everyone,
I am trying to analyse my data from a small plant experiment (for a meeting tomorrow afternoon) and am a beginner to R so I apologise if this is a very basic question.
I carried out a plant experiment examining plant interactions between two species (A and B) under different watering treatments. I had:
- 7 watering treatments (7 different watering frequencies labelled 1-7)
- 3
2004 Jan 05
3
Heeeeeelp! Estimatet Marginal Means of ANOVA needed!
Hello!
I urgently need to know if it is possible (and if so, how to do) to get
the "Estimatet marginal means" from an ANOVA.
Or explained more coplicated: It's about plants sewn in 2 densities & 2
patterns. The Variable is biomass and I also use a Covariate. There are highly
significant differences between density & pattern but I don't know which of the
2 densities
2017 Jun 21
4
Help/ Mathematics
Hi R users,
I need your help to write a code in r that does the following
calculation from three different datasets;
ac = 1/sum (NPP from date 1 to date 2, dataset=1) * (biomass at date 2
-biomass at date 1, dataset = 2) + (littfall at date 2, dataset=3).
all the dates are in yr-month-day format. Which library or function
Should I use to tell R do these calculations of these variables at
2013 Mar 26
2
Problem with nested for-loop
Hello,
I'm working on a problem using nested for-loops and I don't know if it's a
problem with the order of the loops or something within the loop so any
help with the problem would be appreciated. To briefly set up the problem.
I have 259 trees (from 11 different species, of unequal count for each
species) of which I am trying to predict biomass. For each tree species I
have 10000
2011 Aug 24
1
R (&stats) newcomer.... help!
Hi all,
I hope that i've posted this in the correct place. if not, please accept my
apologies (where should this go?)
I have carried out experimental removal of bivalves at 2 intertidal shores.
Bivalves were removed by raking of surface sediments. I wish compare the
biomass values of for a total of 8 species between the 2 shores
My 3 treatments are: Undisturbed Controls (Cont), Procedural
2011 Sep 27
1
ANOVA define as factor or not
Hi all
This is probably a simple problem but somehow I am having much trouble with
finding a solution, so I seek your help!
I have a data-set with continuous response variables. The explanatory
variably is 4xpH treatments (so 8.08, 7.94, 7.81 and 7.71) so also
continuous and not technically factorial.
However I have decided to do Anova's (as well as regression) to explore the
effect of
2013 Jun 28
3
problem with eval(..., parent.frame(1L)) when package is not loaded
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
The lmer() function in the lme4 package has some code of the form
mc <- match.call()
mc[[1]] <- as.name("lFormula")
lmod <- eval(mc, parent.frame(1L))
this is a fairly common idiom in R, found e.g. in lm(), used when
one wants to pass all of the arguments of a function to a different
function (in the case of lm() it's
2017 Jun 30
3
Predict
Sorry for the confusion, here is the edited question.
The data= Stand_Height (attached) is recorded from 12/1/2009 to
12/31/2015 (25 observations) and the other dataset (leafbiom) is
recorded from 10/7/2009 to 12/29/2016 (daily observations).
I want to use the 25 observations of stand height to predict the daily
stand height from 10/7/2009 to 12/29/2016. The daily stand height will
be multiplied
2017 Jun 30
0
Predict
There are a bunch of things wrong here, although without a
reproducible example I can't really fix most of them.
- You're overwriting SH within the loop.
- You're running the regression 2641 times, even though the result
never changes.
- You're never predicting from your linear model using the other data
not in the regression.
- Leaf biomass data is never used for anything. I
2017 Jun 30
0
Predict
Once again, you are over-writing your variable. This time, you are overwriting
the entirety of Stand_Height with the timeseries of height.
Perhaps you should spend some time with one of the good introductory R
resources out there, and think a bit more about your procedure.
Sarah
On Fri, Jun 30, 2017 at 11:23 AM, Ahmed Attia <ahmedatia80 at gmail.com> wrote:
> Sorry for the confusion,
2013 Jul 23
1
Heat Map for species - code from Numerical Ecology with R
Hello, I am relatively new to R and I am working through the code that is provided in the book Numerical Ecology with R and I have run across an error message that I can't seem to figure out. I am using the vegan, ade4, gclus and cluster packages. The code is as follows: # Ordered community table # Species are ordered by their weighted averages on site scores or <- vegemite(spe,