[R] Help with fmodel in statisticalModeling package

[peter dalgaard]

I have no clue about the internals of fmodel() (and no real intention of getting one...), but pragmatically and to avoid getting sidetracked, how about converting the bogus variable to zero-one:

CPS85$bogus <- as.numeric(rnorm(nrow(CPS85)) > 0)

-pd

> On 6 Sep 2019, at 11:57 , Paul Johnston <paul.johnston using manchester.ac.uk> wrote:
> 
> Hi
> 
> Anyone able to help me with this.
> I'm doing a datacamp course and the effect of adding a "bogus variable" to a linear model.
> I make a model and initially fmodel works fine.
> When I have a second model which uses this "bogus variable" it complains about the type of this variable.
> 
> The code below works fine.
> 
> library(statisticalModeling)
> library(mosaicData)
> print(names(CPS85))
> 
> # Add bogus column to CPS85 (don't change)
> CPS85$bogus <- rnorm(nrow(CPS85)) > 0
> cat ("typeof(CPS88$bogus) is:", typeof(CPS85$bogus), "\n")
> # Make the base model
> base_model <- lm(wage ~ educ + sector + sex, data = CPS85)
> print(fmodel(base_model))
> 
> # Make the bogus augmented model
> aug_model <- lm(wage ~ educ + sector +sex  + bogus, data = CPS85)
> #print(fmodel((aug_model)))
> 
> # Find the MSE of the base model
> mean_base <- mean((CPS85$wage - predict(base_model, newdata = CPS85)) ^ 2)
> 
> # Find the MSE of the augmented model
> mean_aug <- mean((CPS85$wage - predict(aug_model, newdata = CPS85)) ^ 2)
> cat("Mean Square Error of base", mean_base,"\n")
> cat("Mean Square Error of aug", mean_aug)
> 
> However if I uncomment #print(fmodel((aug_model)))
> I get
> 
> Error: variable 'bogus' was fitted with type "logical" but type "character" was supplied
> 
> Any pointers gratefully accepted
> 
> Cheer Paul J
> 
> 
> Paul Johnston
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> 
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-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Office: A 4.23
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