Displaying 20 results from an estimated 1200 matches similar to: "ANOVA 1 too few degrees of freedom"
2010 Dec 18
3
use of 'apply' for 'hist'
Hi all,
##########################################
dof=c(1,2,4,8,16,32)
Q5=matrix(rt(100,dof),100,6,T,dimnames=list(NULL,dof))
par(mfrow=c(2,6))
apply(Q5,2,hist)
myf=function(x){ qqnorm(x);qqline(x) }
apply(Q5,2,myf)
##########################################
These looks ok.
However, I would like to achieve more.
Apart from using a loop,
is there are fast way to 'add' the titles to be
2012 Mar 01
1
Parameterization of Inverse Wishart distribution available in MCMCpack and bayesm libraries
Hello Everyone
Both the MCMCpack and the bayesm libraries allow us to make draws from the
Inverse Wishart distribution.
But I wanted to find out how exactly is the Inverse Wishart distribution
parameterized in these libraries.
The reason I ask is the following:
Now its generally standard to express Inverse Wishart as IW(0.5 * DOF,0.5*
Scale). (DOF-> Degree of freedom, Scale -> Scale
2001 Nov 22
2
factanal {mva} question
Hello!
I have a question about the factanal function.
This function returns at the end test statistics like this:
Test of the hypothesis that 4 factors are sufficient.
The chi square statistic is 4.63 on 2 degrees of freedom.
The p-value is 0.0988
Is it possible to get the chi square statistic and the p-value as variables,
not the text on the screen? An object of class "factanal"
2003 May 08
2
Returning the p-value of a factor analysis
Hi there,
Does anyone know how to explicitly refer to the p-value of thet test that
the chosen number of factors is significant in a factor analysis.
It's not in the list of values for the factanal command output yet it is
printed out with the results.
Thanks in advance.
Wayne
Dr Wayne R. Jones
Statistician / Research Analyst
KSS Group plc
St James's Buildings
79 Oxford Street
2012 May 16
1
fitting t copula with fixed dof
I need to fit a t copula with fixed degree of freedom let's say 4. I
do not want to estimate the dof together with correlation matrix
optimally. Instead fix the dof to 4 and only estimate the correlation
matrix in the optimization routine. Is anyone aware of such estimation
method in R.
The packages and functions that I know of can't do this estimation. I
searched online but
2010 Aug 10
2
USDT probes
Hi,
I''m posting a question hoping someone will know the answer off hand thereby reducing my search time. :-)
With USDT probes, the tracepoint is only installed by libdtrace itself, never by the drti ioctl. So whenever I run a program with an USDT probe, no tracepoint is installed. Only after I run the dtrace command the tracepoint is actually installed on the victim process.
My question
2005 Aug 26
3
Matrix oriented computing
Hi,
I want to compute the quantiles of Chi^2 distributions with different
degrees of freedom like
x<-cbind(0.005, 0.010, 0.025, 0.05, 0.1, 0.5, 0.9, 0.95, 0.975, 0.99, 0.995)
df<-rbind(1:100)
m<-qchisq(x,df)
and hoped to get back a length(df) times length(x) matrix with the
quantiles. Since this does not work, I use
x<-c(0.005, 0.010, 0.025, 0.05, 0.1, 0.5, 0.9, 0.95, 0.975,
2008 Sep 09
1
Addendum to wishlist bug report #10931 (factanal) (PR#12754)
--=-hiYzUeWcRJ/+kx41aPIZ
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8bit
Hi,
on March 10 I filed a wishlist bug report asking for the inclusion of
some changes to factanal() and the associated print method. The changes
were originally proposed by John Fox in 2005; they make print.factanal()
display factor correlations if factanal() is called with rotation =
2006 Aug 24
1
how to constrast with factorial experiment
Hello, R users,
I have two factors (treat, section) anova design experiment where
there are 3 replicates. The objective of the experiment is to test if
there is significant difference of yield between top (section 9 to 11)
and bottom (section 9 to 11) of the fruit tree under treatment. I
found that there are interaction between two factors. I wonder if I
can contrast means from levels of
2011 Mar 07
5
Parsing question, partly comma separated partly underscore separated string
Dear R-list,
I have a partly comma separated partly underscore separated string that I am trying to parse into R.
Furthermore I have a bunch of them, and they are quite long. I have now spent most of my Sunday trying to figure this out and thought I would try the list to see if someone here would be able to get me started.
My data structure looks like this,
(in a example.txt file)
Subject
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,]
2008 Oct 15
2
Network meta-analysis, varConstPower in nlme
Dear Thomas Lumley, and R-help list members,
I have read your article "Network meta-analysis for indirect treatment
comparisons" (Statist Med, 2002) with great interest. I found it very
helpful that you included the R code to replicate your analysis;
however, I have had a problem replicating your example and wondered if
you are able to give me a hint. When I use the code from the
2010 Dec 01
2
Lattice dotplots
Dear,
I have a dataset with 4 subjects (see ID in example), and 4 treatment (see
TRT in example) which are tested on 2 locations and in 3 blocs. By using
Lattice dotplot, I made a graph that shows the raw data per location and
per bloc. In that graph, I would like to have a reference line per bloc
that refers to the first treatment (T1). However, I can not find how to do
that.
I can make
2002 May 12
4
Generalized Estimating Functions
Hi,
I'm trying to fit a marginal model via GEE but I'm getting strange
results and few problems.
If I set the working correlation as exchangeable I'm getting the same
fitting when I set as independent. Comparing to SAS results it shouldn't
happen.
If I try to use another working correlation (like AR-M or stat_M_dep), R
just exits without giving any error message.
Another doubt
2006 Mar 03
1
Help with lme and correlated residuals
Dear R - Users
I have some problems fitting a linear mixed effects model using the lme function (nlme library). A sample data is as shown at the bottom of this mail. I fit my linear mixed model
using the following R code:
bmr <-lme (outcome~ -1 + as.factor(endpoint)+ as.factor(endpoint):trt, data=datt,
random=~-1 + as.factor(endpoint) + as.factor(endpoint):trt|as.factor(Trial),
2008 Jun 04
1
"& not meaningful for factors"
I am trying to define groupings from levels of factor variables and this the warning message that R give
"& not meaningful for factors".
The nature of my task is this. I have a variable stage which has the levels (1B, 2A, 2B) - these are the AJCC TNM stages of cancer, and another variable diameter with factor levels ("=< 4", "4 - 6.5, > 6.5; limit values are
2012 Jan 27
1
Confused with Student's sleep data description
I am confused whether Student's sleep data "show the effect of two
soporific drugs" or Control against Treatment (one drug). The reason
is the next:
> require(stats)
> data(sleep)
> attach(sleep)
> extra[group==1]
numeric(0)
> group
[1] Ctl Ctl Ctl Ctl Ctl Ctl Ctl Ctl Ctl Ctl Trt Trt Trt Trt Trt Trt Trt Trt Trt
[20] Trt
Levels: Ctl Trt
> sleep$group
[1] 1 1 1 1 1
2013 Sep 13
1
Creating dummy vars with contrasts - why does the returned identity matrix contain all levels (and not n-1 levels) ?
Hello,
I have a problem with creating an identity matrix for glmnet by using the
contrasts function.
I have a factor with 4 levels.
When I create dummy variables I think there should be n-1 variables (in this
case 3) - so that the contrasts would be against the baseline level.
This is also what is written in the help file for 'contrasts'.
The problem is that the function
2011 Apr 20
2
survexp with weights
Hello,
I probably have a syntax error in trying to generate an expected
survival curve from a weighted cox model, but I can't see it. I used
the help sample code to generate a weighted model, with the addition
of a "weights=albumin" argument (I only chose albumin because it had
no missing values, not because of any real relevance). Below are my
code with the resulting error
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