Displaying 20 results from an estimated 3000 matches similar to: "Bugs/issues with model.tables() (PR#8275)"
2006 Jan 06
1
lmer p-vales are sometimes too small
This concerns whether p-values from lmer can be trusted. From
simulations, it seems that lmer can produce very small, and probably
spurious, p-values. I realize that lmer is not yet a finished product.
Is it likely that the problem will be fixed in a future release of the
lme4 package?
Using simulated data for a quite standard mixed-model anova (a balanced
two-way design; see code for the
2005 Mar 03
0
Baffled by drop1
I've been experimenting with drop1 for my biostatistics class, to obtain the
so-called Type III sums of squares. I am fully aware of the deficiencies of
this method, however I feel that the students should be familiar with it.
What I find baffling is that when applied to a fully balanced design, you
obtain different sums of squares. I've used this for several years in Splus
and R and never
2005 Mar 03
0
Baffled by drop1: Please ignore previous request!
My apologies to the list for sending this without adequate research. I have
found my answer; please ignore! Thanks.
I've been experimenting with drop1 for my biostatistics class, to obtain the
so-called Type III sums of squares. I am fully aware of the deficiencies of
this method, however I feel that the students should be familiar with it.
What I find baffling is that when applied to a fully
2007 Sep 15
1
Cannot get contrasts to work with aov.
I have been trying for hours now to perform an orthogonal contrast through an
ANOVA in R.
I have done a two-factor factorial experiment, each factor having three
levels. I converted this dataset to a dataframe with one factor with nine
treatments, as I couldn't work out what else to do.
I have set up a matrix with the eight orthogonal contrasts that I wish to
perform, but despite
2005 Jan 22
0
statistical test improvement of readability (was average disjunction)
Dear all ReadeRs
I was finding a quick method to improve test readability adding or constructing
(with your help....) one or more function that allow what follow.
Please consider
Trt<-c(1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5)
Block<-c(1,2,3,4,1,2,3,4,1,2,3,4,1,2,3,4,1,2,3,4)
AD2DAT<-c(1.44,2.32,1.68,1.28,0.12,0.08,0.24,0.52,0.12,0.08,0.16,0.28,0.16,0.08,0.12,0.12,0.16,0.08,0.32,0.76)
2011 Dec 11
2
multiple comparison of interaction of ANCOVA
Hi there,
The following data is obtained from a long-term experiments.
> mydata <- read.table(textConnection("
+ y year Trt
+ 9.37 1993 A
+ 8.21 1995 A
+ 8.11 1999 A
+ 7.22 2007 A
+ 7.81 2010 A
+ 10.85 1993 B
+ 12.83 1995 B
+ 13.21 1999 B
+ 13.70 2007 B
+ 15.15 2010 B
+ 5.69 1993 C
+ 5.76 1995 C
+ 6.39 1999
2013 Feb 16
1
odd behavior within R2HTML
Dear R People:
I'm using R2HTML but having a strange result.
Here is the original data:
resp trt block
90.3 A I
89.2 A II
98.2 A III
93.9 A IV
87.4 A V
97.9 A VI
92.5 B I
89.5 B II
90.6 B III
94.7 B IV
87.0 B V
95.8 B VI
85.5 C I
90.8 C II
89.6 C III
86.2 C IV
88.0 C V
93.4 C VI
82.5 D I
89.5 D II
85.6 D III
87.4 D IV
78.9 D V
90.7 D VI
And here are the commands:
> resin1.df <-
2008 Jul 31
0
multiple comparison
Dear all,
I was trying to understand how "multcomp" package works by running the
examples given in the documentation.
However I still don't understand when it comes to multiple comparison set by
user (please refer to "Ksub" in the code). Therefore I run 2 other cases
along with the original example (case 1), with the expectation I'll get the
point from the output. The
2013 Jan 14
1
Tukey HSD plot with lines indicating (non-)significance
Dear list members,
I'm running some tests looking at differences between means for various
levels of a factor, using Tukey's HSD method.
I would like to plot the data as boxplots or dotplots, with horizontal
significance lines indicating which groups are statistically
significantly different, according to Tukey HSD. Here's a nice image
showing an example of such a graphical
2007 Mar 14
1
How to transform matrices to ANOVA input datasets?
Hello, R experts,
I have a list called dataHP which has 30 elements (m1, m2, ..., m30).
Each element is a 7x6 matrix holding yield data from two factors
experimental design, with treatment in column, position in row. For
instance, the element 20 is:
dataHP[[20]]
col1 col2 col3 trt1 trt2 trt3
[1,] 22.0 20.3 29.7 63.3 78.5 76.4
[2,]
2002 Aug 22
1
aov bug? (PR#1930)
R : Copyright 2001, The R Development Core Team
Version 1.4.0 (2001-12-19)
R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type `license()' or `licence()' for distribution details.
R is a collaborative project with many contributors.
Type `contributors()' for more information.
Type `demo()' for some demos,
1999 Nov 30
3
model.tables
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2002 Dec 15
2
Interpretation of hypothesis tests for mixed models
My question concerns the logic behind hypothesis tests for fixed-effect
terms in models fitted with lme. Suppose the levels of Subj indicate a
grouping structure (k subjects) and Trt is a two-level factor (two
treatments) for which there are several (n) responses y from each
treatment and subject combination. If one suspects a subject by
treatment interaction, either of the following models seem
2004 Dec 15
1
TukeyHSD & Covariates
Dear R gurus,
I have the following model:
appcov.aov <- aov(yield ~ prevyield + trt + block)
where prevyield is a continuous numeric covariate and trt and block are
factors (yes, I did factor()!)
Now, when I do a TukeyHSD, my diff's are all screwed up!
For instance:
treatment mean for treatmen "E" is 277.25 and for treatment "O" is
279.5, so I figure the diff O-E
2011 May 03
3
ANOVA 1 too few degrees of freedom
I'm running an ANOVA on some data for respiration in a forest. I am having a
problem with my degrees of freedom. For one of my variables I get one fewer
degrees of freedom than I should.
I have 12 plots and I therefore expected 11 degrees of freedom, but instead
I got 10.
Any ideas?
I have some code and output below:
> class(Combined.Plot)
[1] "character"
>
2005 Oct 18
1
RMySQL problems
I get the following error trying to connect to a MySQL database:
> library(RMySQL)
Loading required package: DBI
> drv<-dbDriver("MySQL")
> con<-dbConnect(drv, user="hothand", password=xxx,
host="localhost", dbname="hh03");
Error in mysqlNewConnection(drv, ...) : RS-DBI driver: (could not
connect hothand at localhost on dbname
2010 Feb 26
1
factorial block design with missing data
Hello!
I have read somewhere (somehow, I can't seem to find it again, it's been a couple of months) that when analyzing factorial block design, the position where you put the block factor is important, even more when there are missing values.
I understand that when using anova.lm, the order is sequential, so that if I want to check for a treatment effect, I should put my blocking factor
2006 Mar 09
1
lsa and Rstem?
Dear r-helpers,
I can't get lsa to run because:
> library(lsa)
Loading required package: Rstem
Error in library(pkg, character.only = TRUE, logical = TRUE, lib.loc
= lib.loc) :
'Rstem' is not a valid package -- installed < 2.0.0?
In addition: Warning message:
cannot create HTML package index in: make.packages.html()
> install.packages('Rstem')
Warning in
2007 Jun 21
1
anova on data means
I am transitioning from SAS to R and am struggling with a relatively simple
analysis. Have tried Venables and Ripley and other guides but can't find a
solution.
I have an experiment with 12 tanks. Each tank holds 10 fish. The 12 tanks
have randomly assigned one of 4 food treatments - S(tarve), L(ow), M(edium)
and H(igh). There are 3 reps of each treatment. I collect data on size of
each
2005 Jul 19
1
S4 Dispatching
Is it possible for S4 to (continue) dispatch to a class
created during dispatching? The code below doesn't work;
is this not possible or have I ommitted something?
Concept was to create a SEXP with R_AllocatePtr, give it
a class attribute, and continue dispatch. Example code
below omits multiple parameters that can be different types.
Essentially, any parameter would be converted to an