Displaying 20 results from an estimated 1000 matches similar to: "model diagnostics for logistic regression"
2007 May 14
1
cross-validation / sensitivity anaylsis for logistic regression model
Hi,
I have developed a logistic regression model in the form of (factor_1~ numeric
+ factor_2) and would like to perform a cross-validation or some similar
form of sensitivity analysis on this model.
using cv.glm() from the boot package:
# dataframe from which model was built in 'z'
# model is called 'm_geo.lrm'
# as suggested in the man page for a binomial model:
cost <-
2005 Mar 29
2
R-squared in Logistic Regression
Dear all,
How do I make R show the R-squared (deviance explained by the model) in
a logistic regression?
Below is how I write my syntax. Basically I want to investigate
density-dependence in parasitism of larvae. Note that in the end I
perform a F-test because the dispersion factor (residual deviance /
residual df) is significantly higher than 1. But how do I make R show
the
2006 May 23
1
standardization of values before call to pam() or clara()
Greetings,
Experimenting with the cluster package, and am starting to scratch my head in
regards to the *best* way to standardize my data. Both functions can
pre-standardize columns in a dataframe. according to the manual:
Measurements are standardized for each variable (column), by subtracting the
variable's mean value and dividing by the variable's mean absolute deviation.
This
2006 Oct 04
2
compiling rgdal package on windows / macos
Greetings:
As I am not a windows user, I cannot try this: is it possible to install rgdal
on windows without having to compile it from source ?
Compilation on MacOS is within my abilities, however each time i try and
install the rgdal package it dies complaining that it cannot find
gdal-config --- which was recently installed with GRASS. I have updated my
PATH environment variable, logged
2005 Nov 28
1
overlay additional axes
Greetings,
I am trying to add an extra labled axis in position 3 (top x-axis), with
numbers that do not match up with the existing axes.
Surely this must be possible, and I am just doing it incorectly.
So far I have tried the following:
#make a plot
plot(TIK, type="l", cex=.25, xlim=c(2,32), ylim=c(0,1600))
#try and add a new axis with different numbers in position 3
2006 Apr 10
2
passing known medoids to clara() in the cluster package
Greetings,
I have had good success using the clara() function to perform a simple cluster
analysis on a large dataset (1 million+ records with 9 variables).
Since the clara function is a wrapper to pam(), which will accept known medoid
data - I am wondering if this too is possible with clara() ... The
documentation does not suggest that this is possible.
Essentially I am trying to
2006 Oct 25
1
any good way to convert sp class objects to splancs object
Greetings:
are there any simple ways to convert an sp class object to a splancs ppp class
object, outside of reading the coordinates and computing a bounding box?
cheers,
--
Dylan Beaudette
Soils and Biogeochemistry Graduate Group
University of California at Davis
530.754.7341
2007 May 28
1
off-topic: affine transformation matrix
This may sound like a very naive question, but...
give two lists of coordinate pairs (x,y - Cartesian space) is there any simple
way to compute the affine transformation matrix in R.
I have a set of data which is offset from where i know it should be. I have
coordinates of the current data, and matching coordinates of where the data
should be. I need to compute the composition of the affine
2007 Feb 27
1
prop.test or chisq.test ..?
Hi everyone,
Suppose I have a count the occurrences of positive results, and the total
number of occurrences:
pos <- 14
total <- 15
testing that the proportion of positive occurrences is greater than 0.5 gives
a p-value and confidence interval:
prop.test( pos, total, p=0.5, alternative='greater')
1-sample proportions test with continuity correction
data: 14 out of
2006 Sep 20
2
mysterious error on compile R 2.3.1
Getting a very strange error with a new install of R from source on x86;
make[3]: Leaving directory `/tmp/R.INSTALL.r20887/cluster/src'
** R
** data
** moving datasets to lazyload DB
Error in factor(c(1, 2, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1), :
invalid labels; length 2 should be 1 or 1
Execution halted
ERROR: lazydata failed for package 'cluster'
** Removing
2006 Nov 07
0
evaluation of 2 matrices: categorical comparison
Greetings,
I have two matrices, read in from raster data stored in GRASS. Each matrix
represents the output of a aggregation process on categorical data (Nomial /
Ordinal) - derived from imagery.
I have compared these two data by the following methods:
***** pretending the data is continuous approaches (flawed i am sure...)
1. computing a difference map by computing the absolute difference
2006 Mar 02
1
extracting RGB values from a colorspace class object
Greetings,
After pouring over the documentation for the 'colorspace' package, I have not
been able to figure out how the plot() method converts colorspace coordinates
to RGB values for display on the screen. I am convert between colorspaces
with the various as() methods... but cannot seem to find a way to extract RGB
(i.e. for displaying on a computer screen) triplets from color space
2006 Jul 31
1
questions regarding spline functions
Greetings,
A couple general questions regarding the use of splines to interpolate depth
profile data.
Here is an example of a set of depths, with associated attributes for a given
soil profile, along with a function for calculating midpoints from a set of
soil horizon boundaries:
#calculate midpoints:
mid <- function(x) {
for( i in 1:length(x)) {
if( i > 1) {
a[i] = (x[i] -
2006 Jul 12
2
YART (Yet Another Rails Talk)
This morning I gave a talk on Rails to the NYC CTO Club. The slides
for are online at
http://www.io.com/~jimm/writing/rails_ctoclub/s5/index.html. Hover
over the bottom right corner of the window to see the navigation
controls, including the one that brings up the notes. Printing the
slides works really well; the presentation includes CSS that formats
the whole thing for print output.
The main
2006 Feb 23
1
PostgreSQL CASCADE not copied to test db
When the unit test harness creates a test database from the
development database, the ON DELETE CASCADE constraints I have on my
foreign keys are not copied into the test database. (I can tell by
looking at db/development_structure.sql.)
That means the fixtures can''t load/unload from the test database
properly. In other words, all my tests fail with the same error
message:
2005 Jan 17
1
discretization
Hi, there:
I have a variable whose distribution is far from
normal and its qqnorm is S-shape, like a logisitic
plot. My purpose is to discretize it into 2 or 3
classes. (basically, a transformation from quantative
to discrete). I am wondering if there is a good way to
do that.
thanks,
Ed
2006 Aug 10
1
Web service SOAP URLs started failing with 1.1.4 or using 1.1.2 security patch
Railers,
I''m trying to figure out why invocations to my Web service URLs work
with Rails 1.1.2 but fail both with Rails 1.1.4 (and 1.1.5) and when I
apply the new 1.1.2 security patch to Rails 1.1.2.
It looks like they are failing with SOAP clients but succeeding with
XML-RPC clients.
The URL that used to work is of the form
http://localhost:3000/my_controller/ServiceName/api. When I
2005 Jan 21
2
collection_select
I''m trying to use collection_select, but it''s not working as I expect. The
list populates correctly but the current value is not selected.
@question contains a topic (via topic_id), and @topics is the list of all
topics. Here''s my attempt to create a drop-down list of the topics.
form("question") do | form |
form << content_tag("b",
2005 Jun 30
2
PESQ results for speex 1.0.3
Francois Menard (Mailing List Account) wrote:
>
> did you try speex in wideband mode ... what bitrate?
>
> f.
15kbps mode. It does significantly better with a different
speaker (the male does better than the female), as well.
I'm considering purchasing a commercial PESQ license and wrap
the PESQ software in a server application. I could then allow
other folks to run PESQ
2012 Nov 07
2
pseudo R-squared with likfit (geoR)
We want to compute a pseudo R-squared for a model whose parameter
estimation was based on maximum likelihood (function likfit, package geoR).
I tried to compute the R2 proposed by Maddala (1983) which compare the
maximized likelihood for the model without any predictor and the
maximized likelihood for the model with all predictors.
I got a really low value (0,01%). Did I miss something? Are