Displaying 20 results from an estimated 8000 matches similar to: "glm: offset"
2008 Mar 02
3
emacs and R
At the suggestion of many people, I have installed emacs on my linux (Fedora 8.0) computer with the intention of using emacs as window interface to R (2.6.0). I have gone though the emacs tutorial and don't see any information about how I should use emacs to run R. Can anyone suggest a document that I might read? In the past I have used R on a Windows XP system and used the built-in windowing
2007 Oct 01
4
data structure with coefficients, and call from lm()
Widows XP
R 2.3.1
I have been trying to make a data structure that will contain both the coefficients from a linear regression along with column and row titles AND the call, i.e.
myreg<-lm(y~x+y+z)
whatIwant<-cbind(c(summary(myreg)$call,"",""),summary(myreg)$coefficients)
Neither the statement above, nor any one of twenty variations I have tried work. I would appreciate
2011 Jan 04
5
Page eject and clearing the console
(1) I know that \n when used in cat, e.g. cat("\n") produces a line feed (i.e. skips to the next line). Is there any escape sequence that will go to the top of the next page?
(2) I know that control L will clear the console. Is there an equivalent function or other means that can be used in R code to clear the console?
Thanks,
John
John David Sorkin M.D., Ph.D.
Chief, Biostatistics
2011 Oct 28
4
Contrasts with an interaction. How does one specify the dummy variables for the interaction
Forgive my resending this post. To data I have received only one response (thank you Bert Gunter), and I still do not have an answer to my question.
Respectfully,
John
Windows XP
R 2.12.1
contrast package.
I am trying to understand how to create contrasts for a model that contatains an interaction. I can get contrasts to work for a model without interaction, but not after adding the
2017 Oct 23
2
Syntax for fit.contrast (from package gmodels)
David,
Again you have my thanks!.
You are correct. What I want is not technically a contrast. What I want is the estimate for "regional" and its SE. I don't mind if I get these on the log scale; I can get the anti-log. Can you suggest how I can get the point estimate and its SE for "regional"? The predict function will give the point estimate, but not (to my knowledge)
2013 Feb 05
3
Non linear programming: choose R that minimizes corr(y, x^R)
I am looking for a package that will allow me to choose R (a real number) that minimizes the correlation of y and x^R, i.e.
find R such that corr(y,x^R) is minimized. Any suggestions for packages I might look at would be helpful.
Thanks,
John
John David Sorkin M.D., Ph.D.
Chief, Biostatistics and Informatics
University of Maryland School of Medicine Division of Gerontology
Baltimore VA
2016 Apr 07
0
using apply to a data frame
??I would like to apply a function, fract, to the columns of a
dataframe. I tried the following
apply(data5NonEventEpochs,2,fract)
but, no surprise it did not work as apply works on matrices not data
frames. How can I apply a fuction to the columns of a data frame? (I
can't covert data5NonEventsEpochs to a matrix as it contains character
data).
Thank you,
John
John David Sorkin M.D., Ph.D.
2006 Dec 09
7
Simulation with R
An apparatus exists whereby a collection of balls is displaced to the
top of a stack by suction. A top level (Level 1) each ball is shifted
1 unit to the left or 1 unit to the right at random with equal
probability. The ball then drops down to level 2. At Level 2, each
ball is again shifted 1 unit to the left or 1 unit to the right at
random. The process continues for 15 levels and the balls are
2017 Oct 23
1
Syntax for fit.contrast (from package gmodels)
David,
predict.glm and se.fit were exactly what I was looking for.
Many thanks!
John
John David Sorkin M.D., Ph.D.
Professor of Medicine
Chief, Biostatistics and Informatics
University of Maryland School of Medicine Division of Gerontology and Geriatric Medicine
Baltimore VA Medical Center
10 North Greene Street
GRECC (BT/18/GR)
Baltimore, MD 21201-1524
(Phone) 410-605-7119
(Fax)
2017 Oct 23
0
Syntax for fit.contrast (from package gmodels)
> On Oct 22, 2017, at 5:01 PM, Sorkin, John <jsorkin at som.umaryland.edu> wrote:
>
> David,
> Again you have my thanks!.
> You are correct. What I want is not technically a contrast. What I want is the estimate for "regional" and its SE.
There needs to be a reference value for the contrast. Contrasts are differences. I gave you the choice of two references
2007 Jan 18
3
selecting rows for inclusion in lm
I am having trouble selecting rows of a dataframe that will be included
in a regression. I am trying to select those rows for which the variable
Meno equals PRE. I have used the code below:
difffitPre<-lm(data[,"diff"]~data[,"Age"]+data[,"Race"],data=data[data[,"Meno"]=="PRE",])
summary(difffitPre)
The output from the summary indicates that
2010 Dec 29
6
icon for an R package
I'm looking for an icon to represent an R package. Perhaps something like
http://cdn2.iconfinder.com/data/icons/DarkGlass_Reworked/128x128/apps/package.png
but with the R logo rather than KDE.
--
Michael Friendly Email: friendly AT yorku DOT ca
Professor, Psychology Dept.
York University Voice: 416 736-5115 x66249 Fax: 416 736-5814
4700 Keele Street Web:
2017 Oct 22
3
Syntax for fit.contrast (from package gmodels)
David,
Thank you for responding to my post.
Please consider the following output (typeregional is a factor having two levels, "regional" vs. "general"):
Call:
glm(formula = events ~ type, family = poisson(link = log), data = data,
offset = log(SS))
Deviance Residuals:
Min 1Q Median 3Q Max
-43.606 -17.295 -4.651 4.204 38.421
Coefficients:
2009 Dec 08
2
lm: RME vs. ML
windows XP
R 2.10
As pointed out by Prof. Venables and Ripley (MASS 4th edition, p275), the results obtained from lme using method="ML" and method="REML" are often different, especially for small datasets. Is there any way to determine which method is preferable for a given set of data?
Thanks,
john
John David Sorkin M.D., Ph.D.
Chief, Biostatistics and Informatics
2010 Apr 26
4
concise syntax for selecting multiple rows
I would like to select rows if a row contains any one of several values. I can do the selection as follows:
result[,"Subject"]=="JEFF" | result[,"Subject"]=="BG"
But this is very unwieldily if one wishes to select many, many rows as one has to continuously repeat the source:
result[,"Subject"]=="JEFF" |
2010 Dec 24
3
Passing a data frame or matrix and working with a column of the data frame or matrix
I am trying to learn more about how to write functions. I would like to pass a data frame (or matrix) and depending on the parameters passed to the function work with a given column of the data frame or matrix. My function, learnfn is given below as are two calls to the function. The first call is an attempt to print the x column from the data frame, the second call is an attempt to print the y
2011 Jan 12
5
2d plot with modification of plotting symbol to indicate third dimension.
I would like to plot 3-dimensional data on a two-dimensional scatter-plot.
Is there a way I can automatically modify the plot symbol (e.g. changing size or color) to indicate the value of a third variable? E.g. How can I plot weight vs. age and indicate the value of muscle mass for each value weight-age pair by making the plot point proportional to the subject's muscle mass?
Thanks,
John
2006 Nov 21
2
sample size for linear regression
Is there an R function that can be used to calculate a sample size for a
linear regression:
i.e.
Given a linear regression:
y=f(x,z)
i.e. fit1<-lm(y~x+z)
is there a function which can be passed coef(z), SE(z), and other
parameters to determine a sample size based on z, SEz and other
information from the regression?
Thanks,
John
John Sorkin M.D., Ph.D.
Chief, Biostatistics and Informatics
2008 Sep 20
2
selecting from a series of integers with pre-determined probabilities
R 2.6
Windows XP
I need to select from the integers 1,2,3,4,5 with some pre-determined probability, e.g. probability of selecting 5 80%, probability of selecting 1 or 2 or 3 or 4 20%. Any suggestions for how I might accomplish this? I need to do it very efficiently as I will be doing it 500,000 times.
Thanks
John
John David Sorkin M.D., Ph.D.
Chief, Biostatistics and Informatics
University of
2007 Mar 26
4
Problem dropping rows based on values in a column
I am trying to drop rows of a dataframe based on values of the column PID, but my strategy is not working. I hope someoen can tell me what I am doing incorrectly.
# Values of PID column
> jdata[,"PID"]
[1] 16608 16613 16355 16378 16371 16280 16211 16169 16025 11595 15883 15682 15617 15615 15212 14862 16539
[18] 12063 16755 16720 16400 16257 16209 16200 16144 11598 13594 15419 15589