From huh420 at dreamwiz.com  Mon Dec 14 21:25:10 2009
From: huh420 at dreamwiz.com (huh420 at dreamwiz.com)
Date: Mon, 14 Dec 2009 21:25:10 +0100 (CET)
Subject: [Rd] New version weighted mean differs from the old one (PR#14142)
Message-ID: <20091214202510.BF0DA282EF29@mail.pubhealth.ku.dk>

Full_Name: Myung-Hoe Huh
Version: 2.10
OS: Windows
Submission from: (NULL) (116.120.84.194)


New Version (2.10.0) weighted mean produces unreasonable result: see below.

     wt <- c(5,  5,  4,  1)/15
     x <- c(3.7,3.3,3.5,2.8)
     x[4] <- NA
     (xm <- weighted.mean(x,wt,na.rm=T))

Outcome is 

>      (xm <- weighted.mean(x,wt,na.rm=T))
[1] 3.266667

The number is obtained by treating x[4] <- 0

I think the old version(2.8.0)'s weighte mean is more reasonable. The old output
was

>      (xm <- weighted.mean(x,wt,na.rm=T))
[1] 3.5

The number si obtained ignoring the x[4], which is NA.



[Rd] New version weighted mean differs from the old one (PR#14142)
huh420 at dreamwiz.com