Re: [R] anova p value extraction

From: H. Paul Benton <hpbenton_at_scripps.edu>
Date: Wed, 07 May 2008 18:17:09 -0700

Yea the anova object seems to be odd. It's not S4 so that's why I tried originally the attr() funtion but....

summary(pb)$Pr(>F)

Error: unexpected '>' in "summary(pb)$Pr(>"
> summary(pb)$Pr

NULL
> summary(pb)@Pr(>F)

Error: unexpected '>' in "summary(pb)@Pr(>"
> summary(pb)@Pr(F)

Error: no slot of name "Pr" for this object of class "summary.aov" In addition: Warning message:
trying to get slot "Pr" from an object (class "summary.aov") that is not an S4 object
>

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markleeds_at_verizon.net wrote:
> Hi: it's probably the Pr(> F) element so just access it by
>
> sum<-summary(whatever).
>
> then sum$Pr(>F) will probably work. But make sure that's it because
> usually the name is pval or pvalue etc so I'm
> surprised about the weird name.
>
>
>
>
> On Wed, May 7, 2008 at 8:47 PM, Paul Benton wrote:
>
>> hello all,
>>
>> Quick question, how do I get the p value out of the anova?
>>
>> Thanks,
>>
>> Paul
>>
>>> pb<-aov(as.numeric(diff[5,16:33]) ~ grF)
>>> summary(pb)
>> Df Sum Sq Mean Sq F value Pr(>F)
>> grF 3 2.7860e+10 9.2867e+09 4.2236 0.02534 *
>> Residuals 14 3.0783e+10 2.1988e+09
>> ---
>> Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
>>> str(summary(pb))
>> List of 1
>> $ :Classes 'anova' and 'data.frame': 2 obs. of 5 variables:
>> ..$ Df : num [1:2] 3 14
>> ..$ Sum Sq : num [1:2] 2.79e+10 3.08e+10
>> ..$ Mean Sq: num [1:2] 9.29e+09 2.20e+09
>> ..$ F value: num [1:2] 4.22 NA
>> ..$ Pr(>F) : num [1:2] 0.0253 NA
>> - attr(*, "class")= chr [1:2] "summary.aov" "listof"
>>> attr(summary(pb), "Pr(>F)")
>> NULL
>>
>> ______________________________________________
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>
>

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