search for: sdrat

Displaying 2 results from an estimated 2 matches for "sdrat".

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2010 Mar 22
0
using lmer weights argument to represent heteroskedasticity
...am able to assign each unit uniquely to one of four groups and I am willing to treat the relative error variances of the groups as known. I.e. I would be able to specify the model I want to fit in lme() using a weights statement of the form "weights = varIdent(form = ~1 | group, fixed = knownSDratios)". I am trying to figure out how I can concoct a "weights" argument for lmer() that will fit this same model. In particular, since the reported inferences about fixed effects parameters are not invariant to how the weights passed to lmer() are scaled, I am trying to understand h...
2013 Feb 20
0
Bayesian mixing model
...79383 14.68013 RoadRunoff 9.177297 1.9034304 0.4618634 22.22206", header=TRUE) ...and geochemistry for 1 target sediment called Dat: Dat<-read.table(text=" CaO MgO Na2O Al2O3 Targethf 15.741 1.346 0.368 19.872", header=TRUE) I have absolute stdev on the sources called adssdRat: abssdRat<-read.table(text=" CaO MgO Na2O Al2O3 Topsoils 1.8552515 0.1135672 0.06212094 1.491125 ChannelBanks 9.8400162 0.1401057 0.08599080 2.708710 FieldDrains 2.3896499 0.1961217 0.02545431 4.300644 RoadRunoff 0.7780579 0.1749869 0.02848264 1.1167...