Re: [R] Help with reading code

Thank you, Steven. It helps! Best, Dana Steven McKinney wrote: > > Hi Dana > >> -Original Message- >> From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] >> On Behalf Of Dana77 >> Sent: Wednesday, December 03, 2008 3:24 PM >> To: r-he

[R] Help with reading code

I would like to give out the equation for calculating the maximum likelihood. Below is the code, but I still have problems with it. After I read the code, I found there are two cases for "w(weights)". If "w" is not zero, then the equation is given as "val <- 0.5 * (sum(log(w)) - N * (log(2 * pi

Re: [R] AIC function and Step function

Thank you, Kingsford. Then I am wondering if there are other ways to write R codes to calculate the "weights" ? Thanks! Dana Kingsford Jones wrote: > > On Sun, Nov 30, 2008 at 5:05 PM, Dana77 <[EMAIL PROTECTED]> wrote: >> >> Thanks for kind help from Ste

Re: [R] AIC function and Step function

Thanks for kind help from Steven and Christos last time. Now I got new problem regarding the codes for calculating the "weights" (w) in "AIC () function". The original code is as below: > getAnywhere("logLik.lm") function (object, REML = FALSE, ...) { res <- object$residuals p <- ob

[R] AIC function and Step function

I would like to figure out the equations for calculating "AIC" in both "step() function" and "AIC () function". They are different. Then I just type "step" in the R console, and found the "AIC" used in "step() function" is "extractAIC". I went to the R help, and found: "The criterion used is