Thanks Dr. Zuur for your reply.
I've followed your suggestion, but it seems that this would only produce
more regressions instead of use the one I produced originally to see if the
original regression would fit new data? Is error analysis the only way i can
make this happen? And how should I write it within the loop so that 5 rows
can be iterated every time?
Alain Zuur wrote:
>
>
> Rbeginner wrote:
>>
>> Hi everyone!
>> 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.
>>
>>
>>
>>
>> One option (out of the many):
>>
>> for (i in 1:2000) {
>>
>> M <- lm(M ~ D + O + S, subset = blah blah, data = YourData)
>> print(summary(M))
>> }
>>
>> The "blah blah" select your rows of data for iteration i.
>>
>> See also:
>>
>> A Beginner's Guide to R (2009). Zuur, Ieno, Meesters.
>>
>> for something very similar. You can dump everything in a text file, or
>> just extract the required info from the summary function (like R^2 etc).
>>
>> Alain
>>
>>
>> Dr. Alain F. Zuur
>> First author of:
>>
>> 1. Analysing Ecological Data (2007).
>> Zuur, AF, Ieno, EN and Smith, GM. Springer. 680 p.
>>
>> 2. Mixed effects models and extensions in ecology with R. (2009).
>> Zuur, AF, Ieno, EN, Walker, N, Saveliev, AA, and Smith, GM. Springer.
>>
>> 3. A Beginner's Guide to R (2009).
>> Zuur, AF, Ieno, EN, Meesters, EHWG. Springer
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> [[alternative HTML version deleted]]
>>
>> ______________________________________________
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>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>>
>
>
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