weighted average - R-help | R Mailing Lists

arun

Mon, Jul 22, 2013 3:44 PM #

In that case:
Master1<- Master

Master1$zGPA<-sapply(seq_len(nrow(Master1[,-1])),function(i) weighted.mean(Master1[i,-1],Units))

Master1$zGPA
#[1]? 0.035121951 -0.003902439? 0.097804878
all.equal(Master,Master1)
#[1] TRUE

A.K.

From: Robert Lynch <robert.b.lynch at gmail.com>
To: arun <smartpink111 at yahoo.com>
Sent: Monday, July 22, 2013 6:35 PM
Subject: Re: [R] weighted average

weighted.mean is the function. ?My apologies for appending an s





On Mon, Jul 22, 2013 at 3:31 PM, arun <smartpink111 at yahoo.com> wrote:

Hi,
>
>I couldn't find the function `weighted.means` using ?weighted.means or ??weighted.means.? It would be useful to provide the library information.
>
>
>
>
>----- Original Message -----
>From: arun <smartpink111 at yahoo.com>
>To: Robert Lynch <robert.b.lynch at gmail.com>
>Cc: R help <r-help at r-project.org>
>Sent: Monday, July 22, 2013 6:26 PM
>Subject: Re: [R] weighted average
>
>Hi,
>May be this helps:
>Master<-read.table(text="
>SID??? B2A??? B2B??? B2C? C2A??? C2B??? C2C??? C118A??? C118B???? C118C
>001??? 0.01??? 0.5????? -0.4??? 1.2????? -1.8??? 0.3????? -0.3????? 0.4?? 0.5
>002??? 0.01??? 0.5????? -0.4??? 0.5????? -0.4??? 1.2????? -1.8????? 0.3? -0.3
>003??? 0.04??? 0.05??? 0.5??? -0.4??? -0.5??? 0.4????? -1.2????? 1.8???? 0.3
>",sep="",header=TRUE)
>?library(matrixStats)
>
>
>? Master$zGPA<-rowWeightedMeans(as.matrix(Master[,-1]),Units)
>?Master
>#? SID? B2A? B2B? B2C? C2A? C2B C2C C118A C118B C118C???????? zGPA
>#1?? 1 0.01 0.50 -0.4? 1.2 -1.8 0.3? -0.3?? 0.4?? 0.5? 0.035121951
>#2?? 2 0.01 0.50 -0.4? 0.5 -0.4 1.2? -1.8?? 0.3? -0.3 -0.003902439
>#3?? 3 0.04 0.05? 0.5 -0.4 -0.5 0.4? -1.2?? 1.8?? 0.3? 0.097804878
>A.K.
>
>----- Original Message -----
>From: Robert Lynch <robert.b.lynch at gmail.com>
>To: r-help at r-project.org
>Cc:
>Sent: Monday, July 22, 2013 6:12 PM
>Subject: [R] weighted average
>
>I am trying to compute GPA from class grades(which have been normallized)
>I have for example the following matrix
>
>Master =
>SID? ? B2A? ? B2B? ? B2C?? C2A? ?? C2B? ? C2C? ? C118A? ? C118B? ?? C118C
>001? ? 0.01? ? 0.5? ? ? -0.4? ? 1.2? ? ?? -1.8? ?? 0.3? ? ? -0.3? ? ?? 0.4
>? ? ? ? ? 0.5
>002? ? 0.01? ? 0.5? ? ? -0.4? ? 0.5? ? ?? -0.4? ?? 1.2? ? ? -1.8? ? ?? 0.3
>? ? ? ? ? -0.3
>003? ? 0.04? ? 0.05? ?? 0.5? ? -0.4? ?? - 0.5? ?? 0.4? ? ? -1.2? ? ?? 1.8
>? ? ? ? 0.3
>etc
>
>Where each column has a zero mean and a standard deviation of 1.? I want to
>calculate a weighted average for each row(student ID) that takes into
>account that
>B2A, C118A, C118B, and C118C are all 4 unit classes, and the rest, B2B,
>B2C, C2A,C2B,C2C are 5 unit classes
>
>I have tried
>Units<-c(4,5,5,5,5,5,4,4,4)
>Master$zGPA <-weighted.means(Master[,2:10],Units)
>
>But that gets me one number and not a vector.
>
>??? [[alternative HTML version deleted]]
>
>______________________________________________
>R-help at r-project.org mailing list
>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.
>
>