Displaying 20 results from an estimated 2000 matches similar to: "Q re Linear Models"
2003 Sep 30
2
FW: error predicting values from the LME
HI all,
I might add some more information in order to possibly solve my problem. I'm
really stuck and no obvious solutions do the trick.
I'm using R 1.7.1 on Windows 2000 with the packages regurarly updated.
I'm using hypothetical data constructed as a pseudo population conforming to
a certain Var-Cov structure.
I might add that just
> predict(level2)
works. But when I add the
2010 Nov 08
2
Several lattice plots on one page
Dear all,
I am trying (!!!) to generate pdfs that have 8 plots on one page:
df = data.frame(
day = c(1,2,3,4),
var1 = c(1,2,3,4),
var2 = c(100,200,300,4000),
var3 = c(10,20,300,40000),
var4 = c(100000,20000,30000,4000),
var5 = c(10,20,30,40),
var6 = c(0.001,0.002,0.003,0.004),
var7 = c(123,223,123,412),
var8 = c(213,123,234,435),
all = as.factor(c(1,1,1,1)))
2008 Jun 04
2
Constructing groupedData objects in nlme - a little problem
Dear R-help,
I am trying to create groupedData objects using the nlme library. I'm
missing something basic, I know:
Here is the first example in ch.1 of Pinheiro & Bates (2000):
library(nlme)
x2=Rail$travel;x1=Rail$Rail;eg1=data.frame(x1,x2);eg1gd=Rail
print(eg1gd)
x11();print(plot(eg1gd))
femodel=lm(x2~x1-1,data=eg1gd)
print(femodel$coefficients)
Result:
x12 x15 x11
2018 Mar 22
3
How do I include a factor in a groupedData object? Meaning and use of inner and outer parameters
Windows 10 64-bit, R-Studio, R version 3.4.3
Several questions relating to groupedData:
(1) I am trying to create a groupedData object that can be used to run an analysis that I have been able to urn using lmer. When I include the interaction terms in the groupedData opbject I get an error message stating that + is not meaningful for factors. How do I include factors in my model? See code and
2018 Mar 22
0
How do I include a factor in a groupedData object? Meaning and use of inner and outer parameters
Dear John
You are only allowed to have the primary covariate on the left hand side
of the vertical bar. Other covariates go in inner or outer.
Michael
On 22/03/2018 12:59, Sorkin, John wrote:
> Windows 10 64-bit, R-Studio, R version 3.4.3
>
>
> Several questions relating to groupedData:
>
> (1) I am trying to create a groupedData object that can be used to run an analysis
2004 Jul 23
2
lme4 groupedData is missing
help.search("groupedData") says that it's part of the lme4 package, but it
appears not to be there (details below). Is this because lme4 is new and
(perhaps) still under development?
> update.packages()
trying URL `http://cran.r-project.org/bin/windows/contrib/1.9/PACKAGES'
Content type `text/plain; charset=iso-8859-1' length 19113 bytes
opened URL
downloaded 18Kb
>
2012 Mar 15
1
Accessing variable's name as an attribute?
Sorry - I suspect this is a very basic query.
I have a data frame structured "flat" (i.e. separate observations for a given subject ID on separate lines). Using the nlme library I create a groupedData object suitable for further analysis thus:
dataset <- groupedData(VARIABLE ~ TIME|ID, data=sfa)
The dataset has a large number of VARIABLES of interest so I want to make use of loops
2005 Mar 17
2
Repeated Measures, groupedData and lme
Hello
I am trying to fit a REML to some soil mineral data which has been
collected over the time period 1999 - 2004. I want to know if the 19
different treatments imposed, differ in terms of their soil mineral
content. A tree model of the data has shown differences between the
treatments can be attributed to the Magnesium, Potassium and organic
matter content of the soil, with Magnesium being the
2006 Dec 14
1
Reverse order of grouping factor in grouppedData
I created the following groupedData object (nlme library):
gd <- groupedData(Conc ~ Time | Subj,
order.groups=T,
FUN = myf,
data=mydata)
The idea of the myf function is to reverse the order of the grouping factor
Subj (or better, reorder from largest to smallest). In the mydata data set,
Subj is an integer that gets converted into a factor in the groupedData
object.
Does anyone
2006 Dec 07
2
groupedData Error Using outer=TRUE
I'm using groupedData from nlme. I set up a groupedData data.frame with
outer=~group1. When I try to plot with outer=TRUE, I get "subscript out
of bounds." This happens most of the time. When it works, I get
spaghetti-type plots for comparing groups. But I don't understand why it
doesn't usually work.
> longa.mod.1.gd <- groupedData(mod1.logit~time|
2007 Dec 27
2
groupedData function not found
Hello,
I'm trying to use the groupedData function and R is giving me the message: Error: can not find function "groupedData"
The code is coming from a textbook so I think it should be correct:
pigs<-data.frame(cbind(pig.time,pig.id,pig.wt))
pig.growth<-groupedData(pig.wt~pig.time|pig.id,data=pigs)
I have added the package "nlme" and to confirm that it was installed
2000 Jul 24
1
How to use groupedData() within a function?
Dear Group:
I have been trying to write an R function within which the function
groupedData() would be used.
The following is a sample program:
#######################
sid<-rep(1:6,times=2)
time<-c(1:12)
trt<-rep(letters[1:3],times=4)
tem<-data.frame(sid,time,trt)
test1.fun<- function(dat=dat)
{
groupedData(time ~ trt|sid, data=dat)
}
test1.fun(dat=tem)
2009 Jul 14
1
Problem with GroupedData
Hi,
I have an original data frame with 8 columns of variables, which are stored in 'data1' frame.
data1 <- read.csv("E:\\PHD GLASGOW UNIVERSITY\\Data\\R\\Colin\\Cailness21.csv")
attach(data1)
names(data1)
[1] "Date" "d" "m" "y" "Time"
[6] "Depth" "Temp"
2008 Jul 19
1
wroung groupedData despite reading Bates and Pinheiro 3 times
Hi everyone. I am trying to add a formula to my data using the groupedData
function.
My experiment consists of randomized block design using fruits, vegetation
and time as factors. The idea is to see if fruits, vegetation and time
explain the abundance of mice. I am using tree density as a covariate.
So I tried to fit the following structure to my data.
>
2001 Nov 19
1
scope of data in groupedData
I'm trying to write a function that has a dataframe as
an argument. Within the function, I call groupedData
to create a grouped-data object from the dataframe
argument. However, the groupedData function doesn't
seem to see the data. I'm guessing it's getting the
argument name rather than its value, but I'm not
positive.
My system: R 1.3.1 on WinNT 4.0 (Pentium II), nlme
2002 Oct 30
1
groupedData
Dear all,
I tried to create a groupedData object, where the grouping factor
is not ordered.
Here ist the code:
library(nlme)
test<-groupedData(conc~Time|Subject,order.groups=F,data=as.data.frame(Theoph))
> getGroups(test)
Levels: 6 < 7 < 8 < 11 < 3 < 2 < 4 < 9 < 12 < 10 < 1 < 5
I still get an ordered factor. As always thanks for your help
peter
2007 Jan 28
1
extra panel arguments to plot.nmGroupedData {nlme}
Greetings,
I have a groupedData (nmGroupedData) object created with the following syntax:
Soil <- groupedData(
ksat ~ conc | soil_id/sar/rep,
data=soil.data,
labels=list(x='Solution Concentration', y='Saturated Hydraulic Conductivity'),
units=list(x='(cmol_c)', y='(cm/s)')
)
the original data represents longitudinal observations in the form of:
2010 Sep 10
1
lme, groupedData, random intercept and slope
Windows Vista
R 2.10.1
Does the following use of groupedData and lme produce an analysis with both random intercept and slope, or only random slope?
zz<-groupedData(y~time | Subject,data=data.frame(data),
labels = list( x = "Time",
y = "y" ),
units = list( x = "(yr)", y = "(mm)")
)
plot(zz)
2005 Apr 26
1
Error in nonlinear mixed-effects model
Dear all,
I am trying to fit a mixed-effects non linear regression, but I have some trouble with it. My data are a balanced panel of 904 subjects with 8 observations (at regular periods) per subject.
The functional form of my model is Y=Aexp(-BX1)X2 +e. I want to allow parameters A and B to vary among subjects and also include an autocorrelation term. I have already fitted a standard nonlinear
1997 Dec 02
1
R-alpha: NextMethod in 0.50-a4
I am encountering difficulty with NextMethod in 0.50-a4. We created a
class of groupedData objects which are data.frames with additional
attributes. The most important attribute is a formula describing
roles of some of the variables in the experimental design.
The class of such objects ends in "groupedData", "data.frame". The
print method for the groupedData class simply