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  1. noetsi

    Removing terms from a model

    So it is a chi squared test against two models one nested in the other? Part of my problem is that Harrell uses very different wording than I am used to.
  2. noetsi

    Removing terms from a model

    That is what I guessed. I have never seen that terminology before. I don't think anyone can assign degrees of freedom :p
  3. noetsi

    Removing terms from a model

    I don't understand how you can generate one p value this way for a set of variables. "8. When you can test for model complexity in a very structured way, you may be able to simplify the model without a great need to penalize the final model for having made this initial look. For example, it can...
  4. noetsi

    Removing terms from a model

    I decided to ask all the questions from the Harrell book in one place :p "As stated in the Preface, the strategy emphasized in this text, stemming from the last philosophy, is to decide how many degrees of freedom can be “spent,” where they should be spent, and then to spend them. If...
  5. noetsi

    Testing linearity assumption in a multiple regression model

    You look to see if there is a non-linear pattern in the residuals. Residuals should not have a specific shape.
  6. noetsi

    Removing terms from a model

    This comes from Harrell's book on regression. I am not sure I understand what he is saying (well that happens a lot). :p "From the above discussion a general principle emerges. Whenever the response variable is informally or formally linked, in an unmasked fashion, to particular parameters that...
  7. noetsi

    Missing data satisfaction research

    Possibly, although it was would be very time consuming to gather it. Particularly given high turnover. I think I am just going to do multiple imputation.
  8. noetsi

    Missing data satisfaction research

    We have a motivation survey where say 75 percent of the individuals respond. If I understand this, this is not an issue of MAR/MNAR/MCAR. You have to make a judgement if you can generalize to the rest of the population, but this is not missing data in the sense multiple imputations would apply...
  9. noetsi

    Interaction effects

    I have a variable that has 4 levels tied to the type of disability. I have a theory that the type of disability influences the impact of services on income gains for customers. I am not sure of the best way to specify an interaction effect for this. Say spending is A, the original 4 level...
  10. noetsi

    Reference coding in SAS Proc Logistics

    I essentially do this another way. :p
  11. noetsi

    Reference coding in SAS Proc Logistics

    Sorry the ''"" n has nothing to do with reference codes or regression. It is how SAS deals with variables that violate it naming conventions such as having spaces between words. I build my models with PROC SQL from state data bases so these conventions are necessary (it is more complicated than...
  12. noetsi

    Making an ordinal response variable binary

    Item Response Theory often uses regression such as Rauch models. I found this kind of amazing from the same author since most analysis treats regression as linear. Relationships among variables are seldom linear, except in special cases such as when one variable is compared with itself...
  13. noetsi

    Employee satisfaction database

    I suspect you will find companies are reluctant to share such information. You might see if public organizations share theirs.
  14. noetsi

    Strange package import error

    No because I have no idea how to do that. I use an automated import function not code I wrote. Also it appears to import although when I try to run it I guess it may not work.
  15. noetsi

    Making an ordinal response variable binary

    I don't really understand why making an ordinal response variable binary is a bad thing. In fact having read logistic regression books I came to the conclusion that making an ordinal response variable binary was safer in terms of interpretation or violation of assumptions. "When the dependent...
  16. noetsi

    Reference coding in SAS Proc Logistics

    If you want the reference to be 0 for everything in the class statement is this the way to do it with genmod? PROC GENMOD DATA=WORK.SORTTempTableSorted PLOTS(ONLY)=None ; CLASS "Age 25 to 44"n (ref ="0") "Associate’s degree"n (ref ="0") "Bachelor’s degree"n (ref ="0") "Beyond a...
  17. noetsi

    Strange package import error

    As far as I can tell the packages downloaded. But I get this strange error recently whenever I download anything. Error in unpackPkgZip(foundpkgs[okp, 2L], foundpkgs[okp, 1L], lib, libs_only, : ERROR: failed to lock directory ‘\\fldvr.net\hq\Users\rthellein\Documents\R\win-library\4.0’ for...
  18. noetsi

    Restricted cubic splines in R

    thanks
  19. noetsi

    Restricted cubic splines in R

    What is the simplest package to do cubic splines in R?
  20. noetsi

    Suppressing the confidence interval

    thanks a lot dason. I have been applying for a job this week and it was very time consuming.