Re: [R-sig-eco] Extracting information from lm results

2008-05-02 Thread Mike Dunbar
to use coef(lm1)[x] rather than lm1$coefficients[x], simply because there is the coef extractor function provided. cheers Mike Dunbar >>> "Stephen Thackeray" <[EMAIL PROTECTED]> 02/05/2008 08:55:10 >>> Dear all, I suspect that this might be a bit basic, but

Re: [R-sig-eco] help with assignment

2008-07-04 Thread Mike Dunbar
Exactly: STEER WELL CLEAR OF attach(). This is just the sort of problem you can get into. Mike >>> tyler <[EMAIL PROTECTED]> 04/07/2008 00:11 >>> "Olivia LeDee" <[EMAIL PROTECTED]> writes: > Would someone mind helping with the following code: > > 1) After attaching the primary dataset > > ambi1

Re: [R-sig-eco] Question About Syntax For Complex ANOVA Design

2008-11-07 Thread Mike Dunbar
Hi Joe I think the command you want is probably simpler than you think: lme(HSP~coast*MBL, random= ~1|site) or lme(HSP~coast+MBL, random= ~1|site) coast and MBL have distinct levels so are fixed and site is random as you say. Having site as random will take into account that there ar

Re: [R-sig-eco] Question About Syntax For Complex ANOVA Design

2008-11-10 Thread Mike Dunbar
in the way that the F ratios are calculated (i.e. what is used to construct the denominator). Since site is random, MS coast should be compared to MS site, rather than MS residual. Again, that's at least from my understanding of how it works in the old-school way, perhaps the REML fittin

Re: [R-sig-eco] Question About Syntax For Complex ANOVA Design

2008-11-10 Thread Mike Dunbar
(apologies - I should have written coast * MBL not ML) I'm not sure of my ground here, but surely do lose something - you wouldn't retain coast:MBL if it's not significant, as you lose degrees of freedom, and this gets worse the more terms and the more interactions you consider. I think it's a

Re: [R-sig-eco] Question regarding a associating a p-value with the residual variance form a lme model

2008-11-11 Thread Mike Dunbar
Dear Charles It's very difficult to tell without more information on what these papers are and what exactly they are saying. Also with your correlation structure, what are you trying to model? corCAR is a continuous AR structure, allowing fractional time points, but you don't have a time varia

Re: [R-sig-eco] Question regarding a associating a p-value with the residual variance form a lme mod

2008-11-18 Thread Mike Dunbar
lose in time are likely correlated. I think the within group order would be proper as it would be the same as the order of year (or tree age if you like, logyearcorr in the model). Would the regular AR be more appropriate ? On Tue, Nov 11, 2008 at 2:55 PM, Mike Dunbar <[EMAIL PROTECTED]> wrote:

Re: [R-sig-eco] nested Kruskal Wallis

2008-11-20 Thread Mike Dunbar
Dear Jude I'm trying to reconcile where you say "it doesn't meet the assumption of homogeneity of variances" with "sample size within fields is small and unequal". With small sample sizes you can easily generate dummy samples with widely differing variances even where the process generating the

Re: [R-sig-eco] mixed model for repeat obs (CL Pressland)

2009-03-26 Thread Mike Dunbar
>From a quick look only, I'm not convinced that the structure of the model as >suggested by Kate, is correct. There is only one random effect in the model, site. Year and Week are specified as random slopes. But they are not in the fixed part of the model, hence I don't think this makes sense.