# [R] Single Factor Anova

Liaw, Andy andy_liaw at merck.com
Fri Apr 2 17:01:32 CEST 2004

So what is your question?  With R-1.8.1 on WinXPPro, I get:

> y <- scan("clipboard")
Read 48 items
> f <- factor(rep(1:2, 24))
> fit <- aov(y ~ f)
> print(unclass(sum.fit)[[1]], dig=15)
Df               Sum Sq              Mean Sq  F value     Pr(>F)

f            1 3.63834187585414e-09 3.63834187585414e-09 15.94673 0.00023268
***
Residuals   46 1.04951729171680e-08 2.28155932981910e-10

---
Signif. codes:  0 `***' 0.001 `**' 0.01 `*' 0.05 `.' 0.1 ` ' 1

Andy

> From: christopher ciotti
>
> Hello all -
>
> As I progress in R I am trying to automate functions I would have
> normally farmed out to Excel, SPSS or Statistica.  Single
> factor anova
> is one of them.  For example, a dataset from NIST StRD
> (http://www.itl.nist.gov/div898/strd/anova/AtmWtAg.html) has
> two groups:
>
> 1             2
>
> 107.8681568   107.8681079
> 107.8681465   107.8681344
> 107.8681572   107.8681513
> 107.8681785   107.8681197
> 107.8681446   107.8681604
> 107.8681903   107.8681385
> 107.8681526   107.8681642
> 107.8681494   107.8681365
> 107.8681616   107.8681151
> 107.8681587   107.8681082
> 107.8681519   107.8681517
> 107.8681486   107.8681448
> 107.8681419   107.8681198
> 107.8681569   107.8681482
> 107.8681508   107.8681334
> 107.8681672   107.8681609
> 107.8681385   107.8681101
> 107.8681518   107.8681512
> 107.8681662   107.8681469
> 107.8681424   107.8681360
> 107.8681360   107.8681254
> 107.8681333   107.8681261
> 107.8681610   107.8681450
> 107.8681477   107.8681368
>
>
> The certified values are (I hope the spaces remain intact):
>
> Sums of                    Mean
> Variation          df      Squares              Squares             F
> Statistic
>
> Between Instrument  1 3.63834187500000E-09 3.63834187500000E-09
> 1.59467335677930E+01
> Within Instrument  46 1.04951729166667E-08 2.28155932971014E-10
>
>
> Any assistance you can offer is greatly appreciated.  Thanks.
>
>
> - --
> chris ciotti (chris_ciotti at yahoo.com)
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>
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