search for: statististics

Displaying 4 results from an estimated 4 matches for "statististics".

2004 Jan 01
1
Barplot errors in MASS script
Reading "Modern Applied Statististics with S" and trying the corresponding examples both in the book and in ../lib/R/library/MASS/script, I'm now trying chapter 4 plotting bars with the following code on a linux box with R 1.8.1: ---------------------- library(MASS) library(lattice) options(echo=T, width=65, digits=5) lung.dea...
2007 Oct 25
0
S-Plus or R programmer for Pharmaceutical Company
We currently have an opening for a S-Plus/R programmer at a large pharmaceutical company. Job Description: S-Plus/ R Programmer -BS/MS in statistics - Solid S-Plus (or R) and SAS programming skills required, minimum 1 year work experience writing functions in S-Plus or R. SAS experience should include writing SAS macros and creating and manipulating ODS datasets. Strong interpersonal and
2006 Apr 11
2
variable selection when categorical variables are available
Dear All, Probably it is not highly relevant question: Why do stepwise regression functions in R (step() or stepAIC()) add/delete categorical variables as a set? For example, I have a four-level factor variable d, so dummies are d1,d2,d3, as stepwise regression operates d, adding or removing, d1,d2,d3 are simultaneously added/removed. What's the concern here if operating dummies individually?
2003 Dec 01
2
wilcoxon-pratt signed rank test in R - drug-effiacy
Hi. I'm going to introduce the R-package for a group of medical doctors later this week and is a little confused about there use of a test named "willcoxon-pratt" for testing if the clinical and biochemical markers has decreased significantly after the use of some drugs for a group of patients. Looking into the R-functions I would in R recommand using a matched-pairs Wilcoxon