Sent from my iPhone
> On Jan 19, 2025, at 2:48 PM, David Winsemius <dwinsem...@comcast.net> wrote:
>
>
> Sent from my iPhone
>
>> On Jan 19, 2025, at 1:57 PM, David Winsemius <dwinsem...@comcast.net> wrote:
>>
>> I don’t understand why you don’t include the full text of the error.
>>
>> —
>> David
>> Sent from my iPhone
>>
>>>> On Jan 19, 2025, at 10:00 AM, Sparks, John via R-help
>>>> <r-help@r-project.org> wrote:
>>>
>>> Hello R-Helpers,
>>>
>>> I was looking into how to test whether the beta coefficient from a
>>> regression would be the same for two different groups contained in the
>>> dataset for the regression.
>>>
>>> When I put that question into google, AI returned a very nice looking
>>> answer (and a couple of variations on it).
>>>
>>> library(car)
>>> data <- data.frame(income = c(30, 45, 50, 25, 60, 55),
>>> education = c(12, 16, 14, 10, 18, 16),
>>> gender = c("Male", "Female", "Male", "Female", "Male",
>>> "Female"))
>>> model <- lm(income ~ education * gender, data = data)
>>> # Test if the beta for "education" is significantly different between
>>> genders
>>> test <- linearHypothesis(model, "genderMale - genderFemale = 0")
>
> That last line appears unlikely to be parsed correctly. In R a “=“ sign is
> interpreted as assignment whereas a “==“ (doubled equals) is a logical
> operator. Since I’ve only got a iPhone at hand I can’t test. In the future
> you should include full text of errors, preferably in the context in which
> they are returned.
>
> As an experiment I asked ChatGPT your question an it suggested
>
> library(car)
> data <- data.frame(
> income = c(30, 45, 50, 25, 60, 55),
> education = c(12, 16, 14, 10, 18, 16),
> gender = c("Male", "Female", "Male", "Female", "Male", "Female")
> )
> model <- lm(income ~ education * gender, data = data)
> # Test if the effect of education differs by gender
> test <- linearHypothesis(model, "education:genderMale = 0")
>
> But I have the same concern about that code as I had with whatever your AI
> produced.
>
> —
> David
After looking at the second and subsequent example in `help(linearHypothesis,
car)` I think chat GPTs attempt looks plausible. The examples don’t use “==“
but they also use just the column names and not the coefficient labeling that
you used.
—
David.
>
>>> print(test)
>>>
>>> This, however, produces an error that I can't find a way to resolve.
>>>
>>> Can this test actually be done in this manner, or is this a case of AI run
>>> amok.
>>>
>>> Guidance would be appreciated.
>>> --John Sparks
>>>
>>>
>>>
>>> [[alternative HTML version deleted]]
>>>
>>> ______________________________________________
>>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide
>>> https://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>
>> ______________________________________________
>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide https://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
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