R help - Jun 2010 - How to 'understand' R functions besides reading R codes

Apologize for not being clearer earlier. I would like to ask again. Thank
Joris and Markleeds for response.

Two examples:

1. Function 'var'. In R, it is the sum of square divided by (n-1) but
not by
n. (I know this in R class)

2. Function 'lm'. In R, it is the residual sum of square divied by (n-2)
not
by n, the same as in the least squares estimate. But the assumption
following that in the method of maximum likelihood.  (I know this by looking
up the book 'Introductory Statistics with R').

But not all functions are explained in the books.

I am thinking whether there is a general way to figure out how R function
works and what is the underlying theory besides looking at the codes
(type var or lm at the  Rprompt). Because R codes are too difficult to
understand.

Thanks

Yi

	[[alternative HTML version deleted]]

There is:
1) read the help files
2) read the vignette (see ?vignette )
2) look up at www.rseek.org
3) check google
4) look at the references mentioned in the help files (or do first if
you're not familiar with the method)
5) ask here

If still nothing :
use another function/method.

Cheers
Joris

On Wed, Jun 23, 2010 at 2:29 AM, Yi <liuyi.feier at gmail.com>
wrote:
> Apologize for not being clearer earlier. I would like to ask again. Thank
> Joris and Markleeds for response.
>
> Two examples:
>
> 1. Function 'var'. In R, it is the sum of square divided by (n-1)
but not by
> n. (I know this in R class)
>
> 2. Function 'lm'. In R, it is the residual sum of square divied by
(n-2) not
> by n, the same as in the least squares estimate. But the assumption
> following that in the method of maximum likelihood. ?(I know this by
looking
> up the book 'Introductory Statistics with R').
>
> But not all functions are explained in the books.
>
> I am thinking whether there is a general way to figure out how R function
> works and what is the underlying theory besides looking at the codes
> (type var or lm at the ?Rprompt). Because R codes are too difficult to
> understand.
>
> Thanks
>
> Yi
>
> ? ? ? ?[[alternative HTML version deleted]]
>
> ______________________________________________
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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.
>


-- 
Joris Meys
Statistical consultant

Ghent University
Faculty of Bioscience Engineering
Department of Applied mathematics, biometrics and process control

tel : +32 9 264 59 87
Joris.Meys at Ugent.be
-------------------------------
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