Re: [R] Assessing temporal correlation in GAM with irregular time steps

2013-09-06 Thread Worthington, Thomas A
Thanks again, Tom -Original Message- From: Gavin Simpson [mailto:ucfa...@gmail.com] Sent: Thursday, September 05, 2013 6:35 PM To: Worthington, Thomas A Cc: r-help@r-project.org Subject: Re: [R] Assessing temporal correlation in GAM with irregular time steps On 3 September 2013 16:

Re: [R] Assessing temporal correlation in GAM with irregular time steps

2013-09-05 Thread Gavin Simpson
> Best wishes > Tom > > -Original Message- > From: Gavin Simpson [mailto:ucfa...@gmail.com] > Sent: Tuesday, September 03, 2013 3:17 PM > To: Worthington, Thomas A > Cc: r-help@r-project.org > Subject: Re: [R] Assessing temporal correlation in GAM with irregular time > st

Re: [R] Assessing temporal correlation in GAM with irregular time steps

2013-09-03 Thread Worthington, Thomas A
l.com] Sent: Tuesday, September 03, 2013 3:17 PM To: Worthington, Thomas A Cc: r-help@r-project.org Subject: Re: [R] Assessing temporal correlation in GAM with irregular time steps It is possible, but you can't use the discrete time or classical stochastic trend models (or evaluate using the ACF

Re: [R] Assessing temporal correlation in GAM with irregular time steps

2013-09-03 Thread Gavin Simpson
It is possible, but you can't use the discrete time or classical stochastic trend models (or evaluate using the ACF). Also, why do you care to do this with regard to DoY? The assumption of the model relates to the residuals, so you should check those for residual autocorrelation. As you are using

[R] Assessing temporal correlation in GAM with irregular time steps

2013-08-28 Thread Worthington, Thomas A
I have constructed a GAM using the package mgcv to test whether the lengths of an emerging insect (Length) varies with day of the year (DOY) and between two sites (SiteCode). The data are collected at irregular time steps ranging from 2 days to 20 days between samples. The GAM takes the form M3