Search found 9 matches

by Mark.McCann
Thu Aug 01, 2013 2:29 pm
Forum: Realcom user forum
Topic: Error message after imputation
Replies: 2
Views: 9858

Error message after imputation

Hello, I set up a 2 level ordinal logistic model in MLwiN and then moved things into Realcom Impute. It did produce imputed datasets, but at the end of the prompt screen I saw the following error messages. I was just wondering: to what extent should I care about these messages, or are they ignorable?
by Mark.McCann
Tue Jul 06, 2010 2:34 pm
Forum: MLwiN user forum
Topic: rmatrix_list already allocated
Replies: 2
Views: 5095

Re: rmatrix_list already allocated

Thanks for that Chris, I've been setting it up again and it seems to work, but occasionally take another turn and start freezing up again. I'll see how the next few models go and decide if there's something going wrong with the pasting of data, or if MLwiN just doesn't like me!
by Mark.McCann
Tue Jul 06, 2010 8:50 am
Forum: MLwiN user forum
Topic: rmatrix_list already allocated
Replies: 2
Views: 5095

rmatrix_list already allocated

Hi folks, I've been working on logistic regression models with about 4,000 pupils in 40 schools, when I go to add a new term I get the pop up rmatrix_list already allocated followed by another popup saying rmatrix_list already allocated(ADDT) and I can't add any terms to the models. Has anyone any i...
by Mark.McCann
Thu Feb 18, 2010 3:47 pm
Forum: MLwiN user forum
Topic: betas and b's
Replies: 1
Views: 4502

Re: betas and b's

Hello Nicky, I'm not 100% what you mean by beta and b here. Have you been using SPSS previously? In SPSS the beta column in the output refers to the standardised coefficients. However in MLwiN, the beta values in the output are the equivalent on the b's in SPSS, they are unstandardised coefficients....
by Mark.McCann
Thu Feb 18, 2010 10:14 am
Forum: MLwiN user forum
Topic: Mean centred variables
Replies: 6
Views: 12674

Re: Mean centred variables

Thanks very much for that Lydia, I suppose by the time I get the models built up I don't need the easiet interpretable reference category, and as the largest will shrink the se's I assume that makes quadrature easier......I have a vague notion that's true from something I was told long ago, but I ha...
by Mark.McCann
Wed Feb 17, 2010 6:11 pm
Forum: MLwiN user forum
Topic: Mean centred variables
Replies: 6
Views: 12674

Re: Mean centred variables

Hi, By ordering the categories, I mean changing the reference category, which you mentioned might help, I usually plump for the largest nominal category or the bottom of an ordinal, might the mid point of an ordinal make a difference to estimation? I tried quantiles and then after reading here I tri...
by Mark.McCann
Tue Feb 16, 2010 1:58 pm
Forum: MLwiN user forum
Topic: Wald tests for random parameters
Replies: 0
Views: 4295

Wald tests for random parameters

Hi folks, How can you calculate a Wald test by hand/calculator for more than one parameter? I'm not working in MLwiN and don't have the equivalent 'intervals and tests' window figured out. Just in case it's different depending on which combination; I'm interested in testing the addition of random sl...
by Mark.McCann
Mon Feb 15, 2010 4:04 pm
Forum: MLwiN user forum
Topic: Mean centred variables
Replies: 6
Views: 12674

Re: Mean centred variables

Thanks very much for this Lydia, it is very helpful. I'm usually not too worried about aiding interpretation of intercepts. I work mostly with discrete data and look for relative differences, controlling for whatever variables and the probabilities from models tend not to interest me themselves. I h...
by Mark.McCann
Mon Feb 15, 2010 9:28 am
Forum: MLwiN user forum
Topic: Mean centred variables
Replies: 6
Views: 12674

Mean centred variables

Hello all, I was wondering about grand mean centreing variable for Multi level models, specifically I'd be interested in answers for the following questions; What are the advantages of using mean centred variables in models (or what are the main advantages)? Do the same advantages apply when using d...