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Message-ID: <a86a994c-d525-a7f1-660c-4b11a574309b@gmail.com>
Date: 2021-01-18T19:34:45Z
From: Duncan Murdoch
Subject: Print out progress reports of add1()
In-Reply-To: <CACCU-vMvzOqRZinGdT5DyhsTiyJENB2KRBRpTxZPNN4wgvBn5A@mail.gmail.com>

On 18/01/2021 12:08 p.m., Chao Liu wrote:
> Thank you Duncan. Do you by chance know any way around?this?

I don't see any need for a trace when there's only one fit being done. 
The tests that are shown are all you need.

Duncan Murdoch


> 
> On Mon, Jan 18, 2021 at 11:58 AM Duncan Murdoch 
> <murdoch.duncan at gmail.com <mailto:murdoch.duncan at gmail.com>> wrote:
> 
>     You are using add1 on an "lm" object, and add1.lm doesn't have a trace
>     parameter.
> 
>     Duncan Murdoch
> 
>     On 18/01/2021 10:55 a.m., Chao Liu wrote:
>      > I have a few questions about using add1(). First of all,
>     according to the R
>      > document of add1(), the trace = TRUE function prints out progress
>     reports
>      > but my attempts to do this have failed several times. So how do
>     we print
>      > out the progress reports of adding terms to the model so as to
>     test for
>      > improved fit (or not)? Also, why the LRT (likelihood-ratio test)
>     value is
>      > not in the output? Any help is greatly appreciated! Example as
>     follows:
>      >
>      > require(graphics); require(utils)
>      > lm1 <- lm(Fertility ~ ., data = swiss)
>      > add1(lm1, scope = .~. + .^2, test="Chisq", trace = TRUE)
>      >
>      > #It seems that no progress report has been printed. Also `LRT` is
>     missing
>      > Single term additions
>      >
>      > Model:
>      > Fertility ~ Agriculture + Examination + Education + Catholic +
>      >? ? ? Infant.Mortality
>      >? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?Df Sum of Sq? RSS AIC Pr(>Chi)
>      > <none>? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 2105 191
>      > Agriculture:Examination? ? ? ?1? ? ? 10.7 2094 192? ?0.6251
>      > Agriculture:Education? ? ? ? ?1? ? ? ?1.8 2103 193? ?0.8399
>      > Agriculture:Catholic? ? ? ? ? 1? ? ? 75.0 2030 191? ?0.1915
>      > Agriculture:Infant.Mortality? 1? ? ? ?4.4 2101 193? ?0.7528
>      > Examination:Education? ? ? ? ?1? ? ? 48.7 2056 192? ?0.2943
>      > Examination:Catholic? ? ? ? ? 1? ? ? 40.8 2064 192? ?0.3378
>      > Examination:Infant.Mortality? 1? ? ? 65.9 2039 191? ?0.2216
>      > Education:Catholic? ? ? ? ? ? 1? ? ?278.2 1827 186? ?0.0099 **
>      > Education:Infant.Mortality? ? 1? ? ? 93.0 2012 191? ?0.1451
>      > Catholic:Infant.Mortality? ? ?1? ? ? ?2.4 2103 193? ?0.8184
>      > ---
>      > Signif. codes:? 0 ?***? 0.001 ?**? 0.01 ?*? 0.05 ?.? 0.1 ? ? 1
>      >
>      > Best,
>      >
>      > Chao
>      >
>      >? ? ? ?[[alternative HTML version deleted]]
>      >
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