From iwhite@staffmail.ed.ac.uk  Thu Aug 22 20:46:00 2002
From: iwhite@staffmail.ed.ac.uk (iwhite@staffmail.ed.ac.uk)
Date: Thu, 22 Aug 2002 21:46:00 +0200 (MET DST)
Subject: aov bug? (PR#1930)
Message-ID: <200208221946.VAA17276@pubhealth.ku.dk>


R : Copyright 2001, The R Development Core Team
Version 1.4.0  (2001-12-19)

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> invisible(options(echo = TRUE))
> R.version
         _
platform i686-pc-linux-gnu
arch     i686
os       linux-gnu
system   i686, linux-gnu
status
major    1
minor    4.0
year     2001
month    12
day      19
language R
> r <- c(10,23,23,26,17,5,53,55,32,46,10,8,10,8,23,0,3,22,15,32,3)
> n <- c(39,62,81,51,39,6,74,72,51,79,13,16,30,28,45,4,12,41,30,51,7)
> trt <- factor(rep(1:4,c(5,6,5,5)))
> Y <- r/n
> z <- aov(Y ~ trt,weights=n)
> summary(z)
            Df  Sum Sq Mean Sq F value    Pr(>F)
trt          3 16.0626  5.3542  12.330 0.0001577 ***
Residuals   17  7.3820  0.4342
---
Signif. codes:  0 `***' 0.001 `**' 0.01 `*' 0.05 `.' 0.1 ` ' 1
> z
Call:
   aov(formula = Y ~ trt, weights = n)

Terms:
                      trt Residuals
Sum of Squares  16.062629  0.395016
Deg. of Freedom         3        17

Residual standard error: 0.1524343
Estimated effects may be unbalanced
>
> # BUG? summary(z) correctly reports the weighted residual sum of squares,
> # but the output from z gives an unweighted residual sum of squares.
> # At the least the discrepancy between the two forms of output is
> # confusing.
> proc.time()
[1] 1.60 0.08 1.65 0.00 0.00
>

======================================
I.White
ICAPB, University of Edinburgh
Ashworth Laboratories, West Mains Road
Edinburgh EH9 3JT
Fax: 0131 667 3210  Tel: 0131 650 5490
E-mail: iwhite@staffmail.ed.ac.uk
======================================


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aov bug? (PR#1930)
iwhite@staffmail.ed.ac.uk