[R] Re gression for loop test HELP! URGENT!

[Rbeginner]

I think the problem is that I've been getting replies about how to make new
regressions, when in fact, I need to use the one I've produced already to
fit new data, 5 rows at a time, to see if it is also a good representation
of further data. From the replies, I'm getting the impression that the only
way I can do that is bye producing more regressions and calculating the
error, but I'm not sure how I should do that, if I get hundreds of new
regressions. I'm thinking, in my primitive programming terms, that I should
ask the system to run through the new data 5 rows at a time and produce some
indication of deviation (error) from the original regression, which would
help me decide whether the original regression is is a good representation
of the new data. Does this make sense?

fm <- lm(M ~ D + O + S)            #this is my original regression, and I
need to use this to fit the test data.
test = data.frame(Mtest,Dtest,Otest,Stest)  #data frame of the test data
attach(test)
for (i in 1:1184){ 
fmtest <- lm(Mtest ~ Dtest + Otest + Stest, subset=(1:5), data=test)  
print(summary(fmtest)) }

#this would only produce a long string of summaries. 
My data is in the form of 
          M       D         O        S
1
2
...
1184

Any suggestions? 



Richard Cotton wrote:
> 
>> I'm new to R, and I've sent this message as a non-member, but since it's
>> pretty urgent, I'm sending it again now I'm on the mailing list (Thanks
>> Daniel for your suggestion nevertheless).
>> 
>> I have calculated a regression in the form of M ~ D + O + S, and I would
>> like to take this regression and test it with other samples, 5 sets of 
> M, D,
>> O, and S at a time(I actually have 2000 sets, so it's probably not 
> efficient
>> to make each a separate set and then index). Since I'll need to test the
>> regression for 400 groups, I thought a for loop might be necessary. I've 
> put
>> everything into a data frame already. Can anyone tell me how to write 
> the
>> code? I'm especially not sure about how to do the for loop.
>> And then how would I calculate the error of how well the test samples 
> fit
>> the original regression?
>> This is for my internship, so it's very urgent.
> 
> Take a deep breath, and think calm thoughts.  Take a look at the posting 
> guide (http://www.r-project.org/posting-guide.html) - it has useful ideas 
> on thinking through your problem.  If you can provide some code then we 
> can see what you want more clearly.
> 
> Show us how you've done your regression what form your data is in.  Tell 
> us which tests you'd like to do on the samples.
> 
> If you are stuck with for loops, then take a look at section 9.2.2 in the 
> Intro to R guide that comes with R.  (Click Help -> Manuals -> an 
> Introduction to R in RGui.)
> 
> Regards,
> Richie.
> 
> Mathematical Sciences Unit
> HSL
> 
> 
> ------------------------------------------------------------------------
> ATTENTION:
> 
> This message contains privileged and confidential inform...{{dropped:22}}
> 
> ______________________________________________
> R-help at r-project.org mailing list
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> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 
> 
> -----
> Regards,
> Richie.
> 
> Mathematical Sciences Unit
> HSL
> 

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