Displaying 15 results from an estimated 15 matches for "glycogen".
2006 Aug 30
1
lmer applied to a wellknown (?) example
...less manual
old-school (?) approach in Sokal, aov in Crawley, and to mixed models by
lmer.
In the example, three treatments (Treatment) with two rats (Rat) each
(i.e six unique rats in total). Three liver preparations (Liver) are
taken from each rat (i.e 18 unique liver preparations), and two glycogen
readings (Glycogen) are taken from each liver preparation (36 readings).
We want to test if treatments has affected the glycogen levels. The
readings are nested in preparation and the preparations nested in rats.
The data can be found here (or on p. 289 in Sokal):
http://www.bio.ic.ac.uk/resear...
2005 Sep 07
1
FW: Re: Doubt about nested aov output
Ronaldo,
Further to my previous posting on your Glycogen nested aov model.
Having read Douglas Bates' response and Reflected on his lmer analysis
output of your aov nested model example as given.The Glycogen treatment has
to be a Fixed Effect.If a 'treatment' isn't a Fixed Effect what is ? If
Douglas Bates' lmer model is modified to...
2008 Apr 04
1
lme4: How to specify nested factors, meaning of : and %in%
...r the rat-liver dataset from the R book (rats.txt from:
http://www.bio.ic.ac.uk/research/mjcraw/therbook/data/ ).
Crawley suggests to analyze this data in the following way:
library(lme4)
attach(rats)
Treatment <- factor(Treatment)
Rat <-factor(Rat)
Liver<-factor(Liver)
m1<-lmer(Glycogen~Treatment+(1|Treatment/Rat/Liver))
The problem that I have with this analysis is that Treatment gets both a fixed
and a random effect [1]. So I would like to remove the fixed effect from
Treatment, but I'm not sure how to do this. Is the following correct?
m2<-lmer(Glycogen~Treatment+(1|T...
2003 Mar 21
2
Trying to make a nested lme analysis
Hi,
I''m trying to understand the lme output and procedure.
I''m using the Crawley''s book.
I''m try to analyse the rats example take from Sokal and Rohlf (1995).
I make a nested analysis using aov following the book.
> summary(rats)
Glycogen Treatment Rat Liver
Min. :125.0 Min. :1 Min. :1.0 Min. :1
1st Qu.:135.8 1st Qu.:1 1st Qu.:1.0 1st Qu.:1
Median :141.0 Median :2 Median :1.5 Median :2
Mean :142.2 Mean :2 Mean :1.5 Mean :2
3rd Qu.:150.0 3rd Qu.:3 3rd Qu.:...
2003 Feb 13
1
fixed and random effects in lme
...g around Mick Crawley dataset "rats" :
http://www.bio.ic.ac.uk/research/mjcraw/statcomp/data/
The advantage is that most work is already done in Crawley's book (page 361
onwards) so I can check what I am doing.
I am tryg to reproduce the nested analysis on page 368:
model<-aov(Glycogen~Treatment/Rat/Liver + Error(Treatment/Rat/Liver), rats)
using lme.
The code:
model1<- lme(Glycogen~Treatment, random = ~1|Rat/Liver, data=rats)
VarCorr(model1)
Variance StdDev
Rat = pdLogChol(1)
(Intercept) 20.6019981 4.538942
Liver = pdLogChol(1)...
2005 Sep 08
1
FW: Re: Doubt about nested aov output
...15)
obs <- gl(15, 1)
subj <- gl(5, 1, 15)
dd <- data.frame(y = y, cond = cond, obs = obs, subj = subj)
l1 <- lmer(y~cond + (1|cond:obs), dd)
l2 <- lmer(y~cond + (1|cond:subj), dd)
l3 <- lmer(y~cond + (1|obs), dd)
Douglas Bates a ??crit:
The difference between models like
lmer(Glycogen~Treatment+(1|Rat)+(1|Rat:Liver))
and
lmer(Glycogen~Treatment+(1|Treatment:Rat)+(1|Treatment:Rat:Liver))
is more about the meaning of the levels of "Rat" than about the
meaning of "Treatment". As I understood it there are three different
rats labelled 1. There is a rat 1 on...
2005 Oct 20
0
lmer and grouping fators
Hi,
I make this model using lme
m.lme <- lme(Glycogen~Treatment,random=~1|rTrt/Liver)
How to make this using lmer?
I try
> m.lmer <- lmer(Glycogen~Treatment+(1|rTrt/Liver))
Erro em lmer(Glycogen ~ Treatment + (1 | rTrt/Liver)) :
entry 0 in matrix[0,0] has row 2147483647 and column 2147483647
Al??m disso: Mensagem de aviso:
/ not meaningful...
2005 Jun 02
0
How to calculate the correct SE in a nested or spliplot anova?
Hi!
How to calculate the correct SE of mean in a nested or spliplot anova?
Nested example:
---------------------
m <- aov(Glycogen~Treatment+Error(Treatment/Rat/Liver))
> m
Call:
aov(formula = Glycogen ~ Treatment + Error(Treatment/Rat/Liver))
Grand Mean: 142.2222
Stratum 1: Treatment
Terms:
Treatment
Sum of Squares 1557.556
Deg. of Freedom 2
Estimated effects may be unbalanced
Stratum 2: Tr...
2007 Dec 20
1
hierarchical linear models, mixed models and lme
...e data of the box 10.5 in the Biometry from
Sokal and Rohlf (2001) using R. This is a three-level nested anova with
equal sample size : 3 different treatments are compared ; 2 rats (coded
1 or 2) / treatment are studied ; 3 preparations (coded 1, 2 or 3) /
rats are available ; 2 readings of the glycogen content / preparations
are realised. Treatment is fixed whereas Rats (nested in Treatment) and
Prep (nested in Rats) are random effects.
According to a previous discussion found in the R-help archives (January
2007), I have tried the following formula :
> box105.lme<-lme(content~treatm...
2017 Sep 19
3
remove quotes from matrix
...also_BCAA)",
"Fatty_Acid_Synthesis", "Fibrinogen_Cleavage_Peptide",
"Fructose,_Mannose_and_Galactose",
"Gamma-glutamyl_Amino_Acid", "Glutamate", "Glutathione", "Glycerolipid",
"Glycine,_Serine_and_Threonine", "Glycogen",
"Glycolysis,_Gluconeogenesis,_and_Pyruvate",
"Guanidino_and_Acetamido", "Hemoglobin_and_Porphyrin", "Histidine",
"Inositol", "Ketone_Bodies", "Leucine,_Isoleucine_and_Valine",
"Long_Chain_Fatty_Acid", "Lysin...
2017 Sep 19
0
remove quotes from matrix
...t; "Fatty_Acid_Synthesis", "Fibrinogen_Cleavage_Peptide",
> "Fructose,_Mannose_and_Galactose",
> "Gamma-glutamyl_Amino_Acid", "Glutamate", "Glutathione", "Glycerolipid",
> "Glycine,_Serine_and_Threonine", "Glycogen",
> "Glycolysis,_Gluconeogenesis,_and_Pyruvate",
> "Guanidino_and_Acetamido", "Hemoglobin_and_Porphyrin", "Histidine",
> "Inositol", "Ketone_Bodies", "Leucine,_Isoleucine_and_Valine",
> "Long_Chain_Fatty_Aci...
2011 Mar 14
0
Non-constancy of variances in mixed model.
...nce.
Another concern of mine is whether I should be using lme as above, or as
a book I read states, re-coding factor levels, and using lmer, for example:
Treatment<-factor(Treatment)
Liver<-factor(Liver)
Rat<-factor(Rat)
rat<-Treatment:Rat
liver<-Treatment:Rat:Liver
model<-lmer(Glycogen~Treatment+(1|rat)+(1|liver)
so with me it might be:
Group<-factor(Group)
Lineage<-factor(Lineage)
Dish<-factor(Dish)
Disk<-factor(Disk)
lineage<-Group:Lineage
dish<-Group:Lineage:Dish
disk<-Group:Lineage:Dish:Disk
model<-lmer(Diameter~Group+(1|lineage)+(1|dish)+(1|disk)
I...
2017 Sep 19
0
remove quotes from matrix
On 19/09/2017 9:47 AM, greg holly wrote:
> Hi all;
>
> I have data at 734*22 dimensions with rows and columns names are
> non-numeric.When I convert this data into matrix then all values show up
> with quotes. Then when I use
> x1= noquotes(x) to remove the quotes from the matrix then non-numeric row
> names remain all other values in matrix disappear.
>
> Your help is
2005 Aug 30
2
Doubt about nested aov output
Hi,
I have two doubts about the nested aov output.
1) I have this:
> anova.ratos <- aov(Glicogenio~Tratamento+Error(Tratamento/Rato/Figado))
> summary(anova.ratos)
Error: Tratamento
Df Sum Sq Mean Sq
Tratamento 2 1557.56 778.78
Error: Tratamento:Rato
Df Sum Sq Mean Sq F value Pr(>F)
Residuals 3 797.67 265.89
Error: Tratamento:Rato:Figado
2017 Sep 19
3
remove quotes from matrix
Hi all;
I have data at 734*22 dimensions with rows and columns names are
non-numeric.When I convert this data into matrix then all values show up
with quotes. Then when I use
x1= noquotes(x) to remove the quotes from the matrix then non-numeric row
names remain all other values in matrix disappear.
Your help is greatly appreciated.
Greg
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