Re: [R] Potential Issue with lm.influence

2019-04-03 Thread Eric Bridgeford
Hey John, Seems fair, and, I agree a more explicit or clear (ie, giving users indications as to why/when the lm.influence is going to misfit the data) warning makes sense in context. Sincerely, Eric On Wed, Apr 3, 2019 at 10:18 AM Fox, John wrote: > Dear Eric, > > I'm afraid that your argument

Re: [R] Potential Issue with lm.influence

2019-04-03 Thread Eric Bridgeford
Hey guys, I appreciate the replies. I agree the issue is easy to catch; wouldn't it make sense to make a warning given that these types of errors (I am sure there are other ways to make the lm.influence have similar NaN performance, simply due to points radically not fitting the data) are relativ

Re: [R] Potential Issue with lm.influence

2019-04-03 Thread Bert Gunter
Second! Bert Gunter On Wed, Apr 3, 2019 at 9:35 AM Richard M. Heiberger wrote: > fortune nomination. > > > The lesson to me here is that if you fit a sufficiently unreasonable > model to data, the computations may break down. > > On Wed, Apr 3, 2019 at 10:18 AM Fox, John wrote: > > > > Dear

Re: [R] Potential Issue with lm.influence

2019-04-03 Thread Richard M. Heiberger
fortune nomination. The lesson to me here is that if you fit a sufficiently unreasonable model to data, the computations may break down. On Wed, Apr 3, 2019 at 10:18 AM Fox, John wrote: > > Dear Eric, > > I'm afraid that your argument doesn't make sense to me. As you saw when you > tried > >

Re: [R] Potential Issue with lm.influence

2019-04-03 Thread Fox, John
Dear Eric, I'm afraid that your argument doesn't make sense to me. As you saw when you tried fit3 <- update(fit, subset = !(Name %in% c("Jupiter ", "Saturn "))) glm.nb() effectively wasn't able to estimate the theta parameter of the negative binomial model. So why would it be better to

Re: [R] Potential Issue with lm.influence

2019-04-03 Thread Fox, John
Hi Peter, Yes, that's another reflection of the degree to which Jupiter and Saturn are out of line with the data for the other planet when you fit the very unreasonable negative binomial model with Volume untransformed. Best, John > On Apr 3, 2019, at 5:36 AM, peter dalgaard wrote: > > Yes,