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    Suggestions for model fit with unusual data set?

    Good morning, I'm struggling to fit a satisfactory model to a data set I have resulting from a systematic review. I performed a systematic review of estimated $ valuations of grasslands and the services they provide. All grasslands provide all services, but some studies only value one of...
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    Defining model - are my samples too small?

    Hello, I am attempting a valuation of a non-market good. This non-market good is made up of a number of component parts. I have conducted a meta-analysis of these valuations and am attempting to model these to establish which explanatory variables given about the good explain values given...
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    Estimating fixed vs. random effects with lme (Hausman?)

    I have ran two lme mixed effects models in R, both using the same fixed effects variables but each with a different random effect variable. My reviewer has said I should use the Hausman test to estimate the effect of fixed vs. random effects. On looking in to this I can only find R code for the...
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    Avoiding spurious regression in meta-regression using stationary variables like GDP

    I have been reading everything I can get my hands on about spurious regression but can't seem to definitively find out what is best in regressing cross-sectional data including non-stationary variables. Example data: Country GDPyearofstudy Popdensyearofstudy Year of study...
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    How can log link still allow negative predicted values?

    I have been attempting to get a meaningful outcome of my data for months, and could really do with some help where to go next. I am attempting to fit a model based on past cost data. y = Total ($/ha/year) (all positive, min = 0.02, max = 2773.05) x1 = Area (ha) x2 = Continent (factor)...
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    Constant negative fitted values...am I missing something?

    Hello all, I'm attempting to fit a model where y variable is a variety of $/ha/year figures (all positive) ranging between 0.01 and 2520. The output of this should always have positive fitted values (none of these values should ever be below 0), and yet I get constant negative fitted values...
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    When removing influential outliers creates more, what then?

    Hello good folks, I am conducting multiple regression for a meta analysis, with the dependent y variable being a range of values ($/ha/year) extracted from studies, and the x variables being a range of geographical and methodological variables. Both the y variable and Area (ha) had a poor...
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    Help with justifying aggregation in SPSS?

    Hi there, I am running a multi-level model on data which is one row per individual survey return, each with Individual ID and Organisational ID. There are variables which can be aggregated in to group, but I first have to justify this aggregation, and have been told to do so via ICC(1)...