search for: pregibon

Hello, Are there any packages/functions available for testing the assumptions underlying assumptions for a good GLM model? Like linktest in STATA and smilar. If not, could somebody please describe their work process when they check the validity of a logit/probit model? Regards, Jay

Is it generally known/has it been previously discussed here that the $aic() component in GLM-family objects (e.g. results of binomial(), poisson(), etc.) does not as implemented actually return the AIC, but rather -2*log-likelihood + 2*(model_has_scale_parameter) ? Can anyone in this forum gauge how a documentation patch would be received? This behaviour does not seem to be documented in ?family

...implementation of ?glm? was written by Simon Davies || working for Ross Ihaka at the University of Auckland, but has || since been extensively re-written by members of the R Core team. || || The design was inspired by the S function of the same name || described in Hastie & Pregibon (1992). actually suggest that it may be hard nowadays to find the original "design specs" that Simon and Ross had used at the time, and also that they only were _inspired_ by the white book chapter 6 (= Hastie & Pregibon (1992)). > Can anyone in this forum gauge how a docum...

Barrett & Ling, JASA, 1992, v.87(417), pp184-191 define general classes of influence measures for multivariate regression models, including analogs of Cook's D, Andrews & Pregibon COVRATIO, etc. As in univariate response models, these are based on leverage and residuals based on omitting one (or more) observations at a time and refitting, although, in the univariate case, the computations can be optimized, as they are in stats::influence() and related methods. I'm i...

...t; > using supports? There are differences in S-PLUS and R > (and the 4th > >edition > > > of MASS supports both, thus ought to tell you this particular > difference > > > between the two). tree() in S-PLUS is written originally > by Clark and > > > Pregibon. If you want that functionality in R, you need > to load the > >`tree' > > > package (available on CRAN), which is an independent > implementation by > one > > > of the co-authors of MASS. > > > > > > Another hint: Look in the `scripts'...

...was written by Simon Davies > || working for Ross Ihaka at the University of Auckland, but has > || since been extensively re-written by members of the R Core team. > || > || The design was inspired by the S function of the same name > || described in Hastie & Pregibon (1992). > > actually suggest that it may be hard nowadays to find the > original "design specs" that Simon and Ross had used at the > time, and also that they only were _inspired_ by the white book > chapter 6 (= Hastie & Pregibon (1992)). > > > > > C...

Hello, I am now running a multiple linear regression program, but I do not know the difference between the command step and stepAIC. Thanks. Maggie [[alternative HTML version deleted]]

my last post was filtered,so I post it again with another title. If I do not make a mistake,the partial association model is an extension of log-linear model.I read a papers which gives an example of it.(Sloane and Morgan,1996,An Introduction to Categorical Data Analysis,Annual Review of Sociology.22:351-375) Can R fit such partial association model? ps:Another somewhat off-topic

I'm following up on a question I posted 8/10/2010, but my newsreader has lost this thread. > Barrett & Ling, JASA, 1992, v.87(417), pp184-191 define general > classes of influence measures for multivariate > regression models, including analogs of Cook's D, Andrews & Pregibon > COVRATIO, etc. As in univariate > response models, these are based on leverage and residuals based on > omitting one (or more) observations at > a time and refitting, although, in the univariate case, the > computations can be optimized, as they are in > stats::influence() a...

Dear all, I am running a logistic regression and this is the output: glm(formula = educationUniv ~ brncntr, family = binomial) Deviance Residuals: Min 1Q Median 3Q Max # ???? ????? ?? ???????? -0.8825 -0.7684 -0.7684 1.5044 1.6516 Coefficients: Estimate Std. Error z value Pr(>|z|) (Intercept) -1.06869 0.01155 -92.487 <2e-16 *** brncntrNo

...rica, the InterContinental Hotels Group and Shell use it. But R has also quickly found a following because statisticians, engineers and scientists without computer programming skills find it easy to use. "R is really important to the point that it's hard to overvalue it," said Daryl Pregibon, a research scientist at Google, which uses the software widely. "It allows statisticians to do very intricate and complicated analyses without knowing the blood and guts of computing systems." It is also free. R is an open-source program, and its popularity reflects a shift in the type...

...k, Bank of America, the InterContinental Hotels Group and Shell use it. But R has also quickly found a following because statisticians, engineers and scientists without computer programming skills find it easy to use. ?R is really important to the point that it?s hard to overvalue it,? said Daryl Pregibon, a research scientist at Google, which uses the software widely. ?It allows statisticians to do very intricate and complicated analyses without knowing the blood and guts of computing systems.? It is also free. R is an open-source program, and its popularity reflects a shift in the type of softwar...